This PDF file contains the front matter associated with SPIE Proceedings Volume 11772, including the Title Page, Copyright information, and Table of Contents.

Phenomenon like resonance energy transfer is widely utilized for many bio-detection schemes where biomolecules actively bind to optical donor and acceptor labeled antibodies to form “sandwich complexes” but the large size of these complexes limits the efficiency of energy transfer, preventing sensitive detection which leads to false outcomes of the tests. In our project, we propose to improve the efficiency of energy transfer through the use of solution-phase optical microcavities. We have designed a novel optical donor that should be capable of performing the energy transfer efficiently over larger distances than the traditional resonance energy transfer limit. We have designed structures where colloidal fluorescent quantum dots (QDs) are precisely located inside dielectric microspheres and the fluorescence of the quantum dots is trapped inside the optical cavities via total internal reflections leading to optical resonances known as whispering gallery modes and the tuning of the experimental parameters will allow us to maximize the coupling of the fluorescence emission of QDs to the modes to achieve the best efficiency of the system. Following the fabrication of the optical donor, we have introduced highly absorbing dye nanoparticles as optical acceptors in the evanescent field of the microcavities and characterized the efficiency of the energy transfer through the optical modes. Now we are developing a technique to impart bio-specificity to the microbeads to detect biomolecules of interest with improved sensitivity and simple methodology.

In this work, a cost-effective optofluidic system is propossed and preliminary experimental results are presented. A microfluidic channel monolithically integrated into a photonic integrated circuit technology is used in conjunc- tion with a cyclo-olefin copolymer (COC) substrate to provide fluidic in- and output ports. We report on initial experimental results as well as on the simple and cost-effective fabrication of this optofluidic system by means of micro-milling.

Self-injection locking to an external fiber cavity is an efficient technique enabling drastic linewidth narrowing and selfstabilization of semiconductor lasers. We introduce a simple dual-frequency laser that employs the same external ring fiber cavity for self-injection locking of a standard semiconductor DFB laser and for the generation of the Stokes light via stimulated Brillouin scattering. In contrast to the previous Brillouin laser configurations, the system spliced from standard telecom components is supplied by a low-bandwidth active optoelectronic feedback that helps to maintain the self-injection locking to provide both the DFB laser line narrowing and permanent coupling between the DFB laser and the fiber ring cavity thus enabling the dual-frequency laser operation. The laser performance characteristics are well superior to the on-board laser modules commonly used with BOTDA. In particular, the configuration reduces the natural Lorentzian linewidth of the light emitted by the laser at pump and Stokes frequencies down to 270 Hz and 110 Hz, respectively, and features a stable 300-Hz-width RF spectrum characterizing beating between two laser outputs. In a direct comparison with the commercial BOTDA, we explore the utilization of our low-cost solution for the BOTDA sensing demonstrating distributed measurements of the Brillouin frequency shift in 10-km sensing fiber with 1.5m spatial resolution.

In this paper, a three-dimensional (3D) depth sensing system based on active structured light field imaging (ALF) is proposed. In light field imaging, one of most commonly used method for depth estimation is based on its Epipolar Plane Image (EPI), in which the slope of line features is related to parallax and is inversely proportional to the depth of the measured object. However, it is difficult to extract the line features accurately only according to the captured texture information of the object, especially in the case of weak texture, repeated texture and noise. Therefore, active phase feature provided by a phase-shifting fringe projection is introduced for this system, with which the line features in EPI can be extracted by simply searching correspondence points with the same phase value. In order to obtain depth map with measuring accuracy, a metric calibration method is proposed to establish the quantitative relationship between the slope of lines and depth. Besides that, due to the existence of distortions in the light field camera (LFC), the correspondence points in EPI cannot fit well enough with linear distribution, another calibration based on the LFC imaging model and Bundle Adjustment (BA) was implemented to correct distortions in the EPI, which can reduce the fitting errors of line features. experiment results proved that calibration method described above is effective, and the built ALF system sensor can work well for 3D depth estimation.

In this work, we present two micro-opto-fluidic platforms for smart recognition of water-based fluids exploiting absorption spectroscopy. The identification of the samples is based on their absorption properties in the near infrared region from 1165 nm to 1650 nm and, in particular, on the analysis of the absorption band of water located around 1450 nm. In the instrumental setup, the fiber-coupled light emitted by a Tungsten lamp is shone onto the micro-devices and the output radiation is directed to an optical spectrum analyzer. The first platform works in reflection by means of a rectangular glass micro-capillary with integrated reflectors. Thanks to the presence of the double metallization, light can cross the capillary channel multiple times in order to enhance measurement sensitivity. The second platform works in transmission and exploits a commercial device with a micro-fluidic polymeric channel. The performances of the sensing platforms were initially theoretically studied by implementing a MATLAB® model based on geometrical optics and Lambert-Beer formula for absorption. Then, experiments were carried out by testing wateralcohol dilutions, proving results in a good level of agreement with the theoretical predictions. We also successfully employed our platforms for specific measurement of the water content in Scottish whisky and Venezuelan white rum liquor. The proposed readout technique is remote, contactless, non-invasive, and thus totally safe. Moreover, borosilicate glass micro-capillary and polymeric channel are both sterile, biocompatible and low-cost devices. These features make our opto-fluidic-platforms highly suitable also for many other applications, ranging from biology to food analysis.

Nitrogen-vacancy (NV) centers are crystallographic defects which provide diamonds with unique physical properties. The centers are known for their intensive, time-stable fluorescence, and an electron spin, which exhibits long coherence time and may be manipulated using external stimuli. Nanodiamonds containing the NV centers are promising tools in biolabeling, biosensing, and drug delivery due to the aforementioned properties of the defects combined with a chemical inertness of a core and an easily functionalized surface of the diamond. Many biochemical reactions are pH-sensitive, therefore, in order to utilize the NV centers for monitoring of such processes, the pH-dependency of the properties of the nanodiamonds needs to be well-understood. Functionalization of the nanodiamonds’ surfaces with biological molecules undergoing pH-triggered changes of conformation, e.g. poly-L-lysine, could not only increase the particles’ biocompatibility and promote cell adhesion, but also possibly enhance pH-sensitivity. In the present study, an impact of pH on the fluorescence, a zeta potential, and a contact angle of the NV centers-containing nanodiamonds dispersed in liquid media is examined. The suspensions were made of commercially available, fluorescent diamond particles in an as-received, unmodified state, and after the poly-L-lysine had been attached to their surfaces via two different procedures – in aqueous, and anhydrous environment. Values of pH of dispersion media were specifically chosen to induce diverse conformation of the poly-L-lysine: from a fully relaxed conformation, through a state of being neither wholly extended, nor helical, to a complete α-helix conformation. The intensity of the photoluminescence emitted by the NV centers has been found to depend on the pH-triggered conformation of the poly-L-lysine attached to the surfaces of the nanodiamonds. The impact of the conformation of the poly-L-lysine on the electric charge of the nanoparticles has also been analyzed. This study confirms the potential of the nitrogen-vacancy centers for optical sensing of pH-triggered processes.

Detection of analytes in aqueous solution with high specificity and sensitivity is of paramount importance in many fields of science, ranging from biomedicine, environmental control, and food quality assessment. Surface-enhanced Raman scattering (SERS) has proven to be a cutting-edge analytical technique for this purpose, by combining the high selectivity of Raman features with the high sensitivity deriving from the plasmonic amplification of Raman signals. Herein, we report a facile and quite effective approach to fabricate large-area Ag-based SERS substrates, exhibiting a porous, coral-like nanotexture. Due to their intrinsic large surface-area and high hot-spot density, the produced substrates appear quite promising for the detection of analytes at trace levels. The nanoporous substrates are produced by Solid-State Dewetting (SSD) of thin Ag-films. In particular, ~30 nm thickness Ag-films are first deposited on glass coverslips by magnetron sputtering. Then, marked roughening is induced by exposing the films to an Inductively Coupled Plasma (ICP) discharge, using synthetic air as feeding gas. The performances of our SERS substrates are characterized in terms of morphology and enhancement factor using CV as probe molecule.

Spectral sensing in the near-infrared range is of increasing interest for application areas ranging from industrial processes to the agri-food sector, as it allows measuring the chemical composition of organic materials in a fast and non-destructive manner. On-field applications demand spectral sensors with a large spectral range, low angular dependence, robust geometry and small footprint, while being manufacturable on large scale at low cost. To meet these requirements, we developed a multi-pixel array of resonant-cavity enhanced detectors using an InP-membrane-on-silicon platform, where each of the 16 pixels provides an individual photoresponse with a number of resonances, which together cover the wavelength range of 800-1700 nm. The pixels consist of two metal mirrors, which enclose an InP p-i-n photodiode with an InGaAs absorber layer and a tuning layer, which varies in thickness to create the individual photoresponses of different pixels. The multi-pixel arrays are fabricated by adhesive wafer bonding followed by a series of lithography steps to define the tuned pixels and metal contacts for the photocurrent read-out. Despite the limited number of measurement channels with broad spectral response, information on the chemical composition of the sample can be directly retrieved using chemometrics. The sensing capabilities for our spectral sensors are demonstrated with two practical application cases: determination of the nutritional information in raw milk and the classification of different plastic types. For both experiments, the photocurrent measurements from the sensor were used directly in regression or classification algorithms based on partial least squares analysis, leading to convincing prediction performance. This shows that the fabricated spectral sensor can retrieve chemical information for a broad set of sensing problems. Simulations have shown that for a specific sensing problem the prediction performance of the spectral sensor can be further improved by an optimized selection of the available spectral responses.

The present article discusses a cost effective technique for the detection and quantification of copper ion by using localized surface Plasmon resonance (LSPR) based fiber optic technique. For the purpose, a small portion of a plastic optical fiber is functionalized with gold nanoparticles which are modified with 4-mercapto benzoic acid (4-MBA). The proposed is very successful in the detection of Cu²⁺ even in trace levels (ppb) in a wide range of real time samples. The results are comparable with the existing detection techniques.

Nowadays, Global Positioning Systems (GPS) are used everywhere for positioning and navigation. However, its use is not suitable in indoor environment, due to power budget constraints and the strong attenuation inside buildings. Therefore, indoors navigation takes advantage of other technologies to infer position. Recently, several Visible Light Positioning (VLP) systems have been reported. Among these technologies, Visible Light Communication (VLC) is one of the most promising, as its operation is based on the use of LED lights, currently widely used in the illumination solutions of most buildings. In this paper, we propose an indoor navigation system based on VLC in an industrial application for automated warehouses, where the navigation of autonomous vehicles (AVG) is supported by VLC. The proposed VLC system establishes bidirectional communication between the infrastructure and the guided vehicles. LED transmitters at the warehouse ceiling support downlink data transmission from the Infrastructure to Vehicle (I2V). This channel provides positioning and navigation of the vehicles, as well as transmission of dedicated messages related to the requested tasks of the management warehouse system to the autonomous vehicles. The uplink channel from the Vehicle to the Infrastructure (V2I) is used to acknowledge the requested tasks and transmit updates on the concluded tasks. Optical transmitters are tri-chromatic white LEDs with a wide angle beam. The characterization of the optical transmitter system is done through MatLab simulations for path loss and VLC channel gain prediction, using the Lambertian model for the LED light distribution. Dedicated receivers based on a-SiC:H/a-Si:H photodiodes with selective spectral sensitivity are used to record the transmitted signal. The decoding strategy is based on accurate calibration of the output signal.

Vehicular Communication Systems are a type of network in which vehicles and roadside units are the communicating nodes, providing each other with information, such as safety warnings and traffic information. In this paper, a traffic controlled intersection is analyzed by using microsimulation. A Vehicle-to-Everything (V2X) communication scenario is stablished and a mesh cellular hybrid network configuration is used. The concept of request/response and relative pose estimation for the management of the trajectory is used, in a two-way-two-way traffic lights controlled crossroad, using Vehicular Visible Light Communication (V-VLC). The connected vehicles receive information from the network and interact with each other and with the infrastructure. In parallel, an intersection manager (IM) coordinates the crossroad and interacts with the vehicles (I2V) using the response distance, the pose estimation and the temporal/space relative pose concepts. The communication between the infrastructures and the vehicles (I2V), between vehicles (V2V) and from the vehicles to the infrastructures (V2I) is performed through V-VLC using the street lamps, the traffic signaling and the headlamps to broadcast the information. Data is encoded, modulated and converted into light signals emitted by the transmitters. Tetra-chromatic white sources are used providing a different data channel for each chip. As receivers and decoders, SiC Wavelength Division Multiplexer (WDM) optical sensor, with light filtering properties, are used. Cooperative localization is realized in a distributed way with the incorporation of the indirect V2V relative pose estimation method. A phasing traffic flow is developed, as Proof of Concept (PoC), to control the arrival of vehicles to the intersection and schedule them to cross at times that minimize delays, A generic model of cooperative transmission based on the graphical representation of indirect relative poses estimation (simultaneous localization and mapping) is analysed. The block diagram expresses that the vehicle’s behavior (successive poses) is mainly influenced by the manoeuvre permission and presence of other vehicles. Results show that the cooperative I2V and V2V messages and the intersection redesigned layout are important issues on traffic control with least dependency on infrastructure.

The sedimentation of solid particles in a liquid is a physical phenomenon that necessitate to be well understood and measured in several cases. In medical diagnosis, a knowledge of the sedimentation speed of red blood cells for example, allows the early diagnosis of various inflammations. In study, optical Micro-Resonators (MRs) are used as sensors to track the dynamical phenomenon of sedimentation of a cloud of nano-particles in water, and the associated consequences on the spectral characteristics of the guided mode are analyzed. A MR is characterized by its eigenvalue, namely the effective index of an optical mode propagating inside. A progressive modification of the environment thus induces a temporal variation of the effective index. Such a variation can be measured by the tracking of the Free Spectral Range (FSR) of the transduced spectra against time. The transduced optical signal is then directed towards an Optical Spectrum Analyzer (OSA) from which spectra are acquired against time. A millimeter tank filled with water is judiciously deposited on the surface of the chip, before the adding of the solution of nano-particles. The spectra are acquired during the whole duration of the process of sedimentation. The data collected this way are then compared to a simple theoretical model describing the sedimentation of a spherical particle in water. Moreover, the sedimentation theory and the derivation of the speed of sedimentation of a spherical particle is presented, plus the presentation of the experimental setup, from the fabrication of the photonic structure by photolithography, to the inclusion of this circuit in an optical characterization platform and the presentation of the data acquisition and treatment program. The experimental results are analyzed and discussed. The differences are around 10% over the theoretical Stokes velocities relating to such sedimentation process. An overall generic curve or spectral response is clearly demonstrated on these sedimentation processes.

Sepsis, defined as the systemic inflammatory response to a confirmed or suspected source of infection, is the most severe infection-related condition and its identification can be particularly difficult in the initial stages. The importance of having a Point-of-care testing platform capable of measuring sepsis biomarkers for a secure early-stage diagnosis is evident to reduce delay in treatment and hence recovery period for the patient. We will report on a simple and cost-effective device which also shows high portability. It is based on the optical detection of labeled essays through a fully-automated fiber probe. Efficient signal collection is obtained by replacing the standard glass substrate with a planar metallo-dielectric multilayer which funnels the emission into a narrow cone around the polar axis [1]. Optical interrogation is implemented with a minimized epi-fluorescence monolithic system directly connected to the fiber. On one hand, optical probes provide the ability to detect low quantities of target molecules without direct contact to the sample; on the other hand, nano-photonics promises to overcome the limitations related to bulk optics with precise and fragile alignment procedures. We will report on preliminary results obtained for a reference dry essays (IgG/anti-IgG) marked with ATTO647N, which demonstrates sensitivity overcoming the requirements for CRP-based sepsis detection. We will also discuss optimization steps which are expected to bring sensitivity beyond the level required for PRC-based sepsis detection. The proposed device is also prone to implementation in microfluidic-based protocols. [1] Checcucci S, Lombardi P., Rizvi S., Sgrignuoli F., Gruhler N., Dieleman F.B.C., Cataliotti F.S., Pernice W.H.P., Agio M., and Toninelli C., Beaming light from a quantum emitter with a planar optical antenna, Light: Science and Applications, Vol. 6, e16245 (2017).

This paper demonstrates a highly effective method for fibre Bragg grating (FBG) inscription into a seven core fibre (7CF) and its application as an effective vector bending sensor. The development of multicore fibres (MCFs) and enabling the fabrication of FBGs into them result in a solution for multi-parameter measurements such as temperature/strain/bending/twist. The FBG in the central core of 7CF is on the neutral axis and therefore it is sensitive only to thermal and insensitive to deformational change, whereas the FBGs in the none-central cores that are evenly distributed over the 7CF cross-section can facilitate the measurement of structure deformation, such as bending, loading and twist. Furthermore, the FBGs in different cores respond to the physical perturbations differently in various orientations, offering vector sensing to measure both amplitude and direction of the structure change. The 7CF-FBG sensors are highly applicable for mechanical structures and flexible medical instruments.

Continuum robots are snake-like elastic structures that can be bent anywhere along their length hence representing ideal tools for minimally invasive surgery. To accurately control these flexible manipulators, 3D shape sensors that are small, sterile, immune to electromagnetic noise, and easy to replace are required. Fiber Bragg Grating (FBG)-based shape sensing is a promising approach for this task. The recently proposed Edge-FBG based shape sensors are particularly promising due to their high flexibility and high spatial resolution. In Edge-FBGs, the amplitude change at the Bragg wavelengths contains the strain information at sensing nodes. However, such sensors are sensitive to changes in the spectrum profile caused by undesired bending-related phenomena. As the existing theories cannot accurately predict the spectrum profile in curved optical fibers, changes in the initial intensity that each Edge-FBG receives are not precisely known. These uncontrolled variations cause inaccuracies in shape predictions and make standard characterization techniques less suitable for Edge- FBG sensors. Therefore, developing a model that distinguishes the strain signal from the changes in the spectrum profile is needed. Machine learning techniques are great tools for studying complex problems, making it possible to explore the full spectrum of the Edge-FBG sensor for identifying patterns caused by bending. In this paper, we studied the feasibility of using a low-cost interrogation system for the Edge-FBGs, considering the minimum required signal-to-noise ratio. We trained a neural network with supervised deep learning to directly extract the shape information from the Edge-FBG spectrum. The designed model can predict the shape of a fiber sensor consisting of five Edge-FBG triplets with less than 6 mm tip error.

Here, we present a novel label-free biosensor based on fiber optic technology which was tested for the detection of a serum inflammatory marker, the C-reactive protein (CRP). The biosensor is based on a long period grating (LPG) inscribed in a double cladding fiber (DCF) having a W-type refractive index profile. Such DCF fiber permits to tune the sensor working point to the so-called mode transition region through etching of the fiber outer cladding. Therefore, a significant enhancement of the refractive index sensitivity, as well as visibility of the grating spectral features were attained since the mode transition was induced in all-silica fiber structure. Subsequently, the so-prepared LPG was coated with a nano-scale layer of graphene oxide, providing carboxylic functional groups for the covalent immobilization of the biological recognition element for the CRP. As a result, a remarkable limit of detection of 320 pg/mL and a large working range of clinical relevance (0.002-100 μg/mL) were achieved during the real time detection of CRP in human serum.

Surface-enhanced Raman scattering (SERS) has established itself as powerful tool for molecular sensing in biology and medicine. The integration of SERS systems with optical fiber is a challenging but potentially very rewarding endeavour. However, efforts to transfer the technology from the laboratory to the clinic have been frustrated by the lack of robust stable and sensitive substrates on the fiber tip, as well as the complexity of interfacing between sample and the substrate itself. Here, we propose the Lab-on-Fiber SERS optrodes, realized on the optical fiber tip by nanosphere lithography. Three types of highly ordered and reproducible SERS-active substrates have been realized: close-packed array (CPA); CPA after sphere removal (SR) and sparse array (SA) of polystyrene nanospheres, covered by a gold thin layer. To optimize the SERS probes, we compared the SERS performances in terms of Enhancement Factor (EF) and reproducibility pertaining to different patterns with different nanosphere diameters and gold thicknesses using the biphenyl-4-thiol (BPT), as target molecule. Moreover, we analysed and compared the SERS spectra of two representative biological probes, bovine serum albumin (BSA, medium molecule) and red blood cells (RBCs), in order to correlate the SERS response to the morphology and hysteric hindrance of the biological target. The SERS analysis indicated that the CPA substrate amplifies the BPT Raman intensity twice as well as the SR and SA substrates, while BSA and RBCs, with the CPA substrate, provide signals comparable to those of SR and SA substrates. Finally, we have optimized a Raman system for SERS optrode operation with efficient lighting and collection via optical fiber.

In the paper some of the applications of tilted fiber Bragg grating-assisted sensors for conducting measurements of parameters of the surrounding media are presented. A short overview of tilted fiber Bragg gratings (TFBGs) structure and operating principle is provided. Some sensor designs utilizing TFBGs are described, including those working on effect of surface plasmon resonance. Experiments were conducted to investigate the test samples of the described sensors and their results are presented.

In this paper, we have designed a refractive index RI sensor based on optical fiber micro-ring resonator for water analysis. Where, we have used the Finite Element Method (FEM) to simulate our design. To Asses the effects of the ideal sensor’s material, we have investigated a comparative study between the two popular materials PMMA and the Silicon, plying on the set of common performance parameters: sensitivity, FWHM, quality factor and Limit of detection(LOD) . As a result, we have found that The PMMA material has attended a maximum sensitivity equal to 763.5nm/RIU . However, the best quality factor and LOD are achived by the silicon material that are respectively given 70300 and 3.79 × 10^-4 and ultra narrow FWHM (0.024).

The cladded U-bent plastic optical fiber (POF) probes with single, triple and quintuple U-bent regions investigated under this study show a RI sensitivity of 2.7, 3.7 and 2.3 absorbance units/RI units respectively. The highest sensitivity obtained here is more than 50% of decladded single U-bent POF probes, however with superior chemical resistance.

We have proposed an experimental study on the effect of the fiber profile parameters on the sensitivity of the tapered optical fiber hydrogen sensors. To study the effects of taper profiles on the sensitivity of the tapered fiber, we divided our study into three experiments where the main parameters of each experiment are tapering angle, waist diameter, and taper length. To examine the effects of taper profile on the sensitivity of tapered fiber, we fabricated eight tapered fibers with varying taper profile. By controlling the fabrication conditions such as pulling duration, pulling speed, heating length, and temperature, tapered fiber with different shapes and properties can be fabricated. By measuring and comparing the sensitivity of the fibers, we found that tapering angle, waist, and length have a significant effect on the sensitivity of the sensor. According to the first part of our experiments, the sensitivity increases from 2.5% to 7% when the angle was increased from 2° to 4°. The second part of our experiments shows that the sensitivity increases from 7% to 8.5% when the length was increased from 10mm to 20mm. The last part of our experiments shows that the sensitivity increases from 4% to 5.5% when the waist diameter was decreased from 35μm to 15μm. To ensure which parameter is being studied, we fixed all other parameters in our experiments. The results of this research show that increasing the tapering angle and length can both help improve sensitivity. Decreasing the waist diameter can also improve sensitivity. We believe that the tapering angle has the most significant effect on the sensitivity of the sensor.

Graphene is emerging as a powerful material for molecular sensors based on surface enhanced infrared absorption (SEIRA), as it exhibits mid-infrared (MIR) plasmonic tunability and extreme light confinement. While MIR probing of biomolecules - such as incubated proteins on graphene nanostructures – was successfully demonstrated in recent years, sensing of gas molecules can be challenging when relying on gas physisorption at the graphene surface. In this work, we employ an ultrathin gas-adsorbing polymer that optimizes gas sensing with graphene plasmons in an unprecedented combination. As a proof-of-concept, we used polyethylenimine (PEI) polymer deposited on top of graphene nanoribbons to selectively adsorb CO2 molecules. The ultrathin PEI layer concentrates the gas close (≤10 nm) to the graphene surface, so that the interaction with the plasmonic near field is significantly enhanced. Critical for the enhancement of graphene plasmon effect is the role of polymer-induced graphene doping. The varying CO2 concentrations can be transduced in changes in the surface optical response by both PEI vibrational mode enhancement and localized surface plasmon resonance (LSPR) modulation related to graphene chemical doping. The latter presents a novel and simpler transduction mechanism with respect to SEIRA effect. Also, we show that the optical response is reversible upon thermal desorption. The proposed hybrid gas sensor can be extended to different functional conductive polymer coatings that adsorb other relevant gases. Moreover, chemical-based doping of graphene plasmonic surfaces opens promising opportunities for gate-free graphene sensors.

A novel hyperspectral sensing imaging taking advantage of engineered all-dielectric metasurfaces supporting bound states in the continuum here is discussed. This approach combines surface-enhanced fluorescence and res- onant shift both based on high-Q resonances in proximity of bound states in the continuum. The amplification of the optical field on resonance allows increasing the fluorescence emission of a dye as a function of the spatial- variant dielectric environment in the near-field of the structure. We first demonstrate the fluorescence emission amplification by resonant pump matching in microscopy configuration. Then, we take advantage of Fano reso- nances in the fluorescence emission to map the spatially variant environment of biological cells. To demonstrate the real implementation of the proposed BIC-enhanced imaging as a platform for biosensing, hyperspectral maps of prostate cancer cells are experimentally reconstructed.

Acoustic-graphene-plasmons (AGPs) are highly confined electromagnetic modes, which carry extreme momentum and low loss in the Mid-infrared (MIR) to Terahertz (THz) spectra. They are therefore enablers of extremely strong light-matter interactions at these long wavelengths. However, owing to their large momentum they are also challenging to excite and detect. Here, we demonstrate a new way to excite AGPs that are confined to nanometric-scale cavities directly from the far-field, via localized graphene-plasmon-magnetic-resonators (GPMRs). This approach enables the efficient excitation of single AGP cavities, which are able to confine MIR light to record-breaking ultra-small mode-volumes, which are over a billion times smaller than their free-space volume.

The realization of periodic plasmonic nanostructures featuring macroscopic scale and easily controllable size and lattice spacing, is a challenging achievement for low-cost nanofabrication tools, which has not been completely explored so far. In this work, periodic array of different metal nanostructures have been easily prepared on large-area by exploiting a modified nano-sphere lithography (NSL) fabrication technique. A valuable ability is to couple the versatility offered by NSL with post-processing tools for a properly engineering of plasmonic nanoparticles. Obtaining dynamic tunability of metal nanostructures will allow the monitoring of electromagnetic near field distribution upon interaction with light of a desired wavelength. A rational design of such singular or collective optical properties can be used to focus and optimize the investigated functional features. Here, Au nano-prisms (NPs) and Au nanohole (NHs) arrays, tailored on the nanoscale, are investigated as innovative sensing platforms and as substrates for surface enhanced Raman scattering (SERS). Their localized “sensing volume”, defined as the penetration depth within which changes of the refractive index can be detected, demonstrated their excellent performances towards single-molecule detection.

We developed a simple model to take into account the refractive index effect on optical path change in multi-wavelength Frequency Modulated Continuous Wave (FMCW) Lidar. Then we developed a scheme to use a single optical frequency comb source to perform Dual Comb Spectroscopy (DCS) experiments and finally we extended this scheme for application of DCS on earth-satellite path using the Doppler induced frequency shift to simulate the second comb source.

GAs in Scattering Media Absorption Spectroscopy (GASMAS) is used to correlate the average pore size within mesoporous alumina samples to the broadening of the absorption lines of oxygen gas and water vapor entrapped within the pores. Collisions of gas molecules cause extra broadening to the absorption linewidths if the average time between collisions is smaller than the inverse of the linewidth of the absorption line. A gas molecule can collide either with another molecule or with the walls of its container. Hence, for a gas entrapped within a porous medium that has an average pore size comparable to the mean free path of intermolecular collisions, collisions of the gas molecules with the walls of the pores can cause extra broadening. This extra broadening is used to estimate the average size of the pores. At atmospheric pressure, the mean free path of intermolecular collision is about 100 nm and thus broadening due to collision with the walls of the pores should be noticeable for pore sizes of order of 100 nm or less. In this work, high resolution tunable singlemode diode lasers at 761 nm and 936 nm are employed to study the absorption from oxygen gas and water vapor, respectively. The samples used are made from porous pure 𝛼-alumina with average pore sizes ranging from 50 to 150 nm.

In this work, a temperature tunable capillary-based polymer whispering gallery modes laser was proposed. The WGM laser device was fabricated by filling the liquid polymer into the capillary tubes. Due to the thermal-optic effect of the polymer, the emission wavelength of the laser device can be continuously tuned from 601.4 nm to 581.9 nm with the varying temperature. Moreover, the suppression of modes was observed owing to the two-ring coupling effect in the capillary cavity. The easy-fabricated and very low-cost method of the temperature tunable WGM laser was verified which exhibits the potentiality for applications of photothermic and sensing devices.

The paper discusses a new method that combines the frequency and phase domains-gated reflectometry. This approach can be applied to a fiber with artificial reflectors to measure the absolute values of the optical paths between reflection points in the fiber in the entire frequency range of the signal, including the zero frequency.

This article demonstrates that the combination of all-dielectric metal oxides sol-gel sensitive materials and metasurfaces, prepared by simple sol-gel methods (dip-coating and soft-Nano Imprint Lithography), can lead to nanocomposite systems with high sensitivity for RI variation and VOC concentration in air detection in spectral shift mode: 4500 nm / RIU ; 0.2 nm / ppm, and in direct reflectance mode: FOM* = 17 ; 0.55 10-3 R / ppm. The metasurface is composed of TiO2 high aspect ratio nano pillars array, replicated from a commercial anti-reflective polymer surface, while the sensitive materials embedding the latter are class II hybrid silica microporous materials containing various types of covalently bonded organic functions. These hybrid layers showed relative significant differences in chemical affinity with different VOCs, which can be exploited to eliminate interferences with air moisture and for qualitative analysis of gas mixtures. We also demonstrated that the presence of the TiO2 metasurface is responsible for the signal intensity increase by almost an order of magnitude in simple reflection mode. This improvement compared to simple Fabry-Perot bi-layer is due to the antenna effect, enhancing the interaction of the confined electromagnetic wave with the sensitive medium. This sol-gel nanocomposite system presents many advantages such as high throughput and low-cost elaboration of the elements, high chemical mechanical and thermal stability ensuring a high stability for detection for long period of time.

Benzene (C₆H₆) is one of the major public health concerns. It is emitted from various natural and anthropogenic sources, like fires and volcanic emissions, petrol service stations, transportation, and the plastics industry. Here, we present our work on developing a new benzene sensor using a widely tunable difference-frequency-generation (DFG) laser emitting between 11.56 and 15 µm (667–865 cm^–1). The DFG process was realized between an external-cavity quantum-cascade-laser (EC-QCL) and a CO₂ gas laser in a nonlinear, orientation-patterned GaAs crystal. We obtained the absorption cross-sections of the Q-branch of the ν4 vibrational band of benzene by tuning the wavelength of the DFG laser between 14.79 and 14.93 μm (670–676 cm^–1). Benzene sensing measurements were performed near 14.84 μm (673.97 cm^–1) with a direct laser absorption spectroscopy scheme. The benzene concentration was varied between ppb and ppm levels. Even with a relatively short optical path-length of 23 cm, our sensor achieved a benzene detection limit of about 10 ppb.

This study investigated innovation of detected the intensity of light via Three Dimension Material Rendering the intensity of light entering the eyes to determine the optimized intensity of light. The innovation of detected the optimized intensity of light via three-dimension material rendering (IDOIL-3D) was rendering into glasses by 3D-printing and can be detected the intensity of visible light by a sensor-controlled by computer language. The sensor for detected of light was determined variable value to notification when a variable value has over limit, the sensor will alert in form biofeedback. IDOL-3D can be helped the wearer reduce the intensity of light entering the eyes.

A digital counting and display circuit for long distance laser rangefinder is presented. The laser rangefinder uses a pulsed Nd:YAG laser emitting in the near-infrared spectral region at the wavelength of 1.06 micrometer to measure distances to targets with a resolution of 5 m, an accuracy of +/- 1.5 m, and a maximum range of 15 km based on a direct time-of-flight method. The detection is achieved with a probability of detection of 0.99 and a probability of false alarm of 1.5X10^-7. The digital circuit is characterized by its simplicity, versatility and reliability. It is placed at the end of an optoelectronic detection chain formed by a silicon avalanche photodiode, a low-noise and fast multistage amplifier, and a fast analog-to-digital converter.

Nano surfaces offer exciting opportunities to implement novel technologies. The effort involved in producing these surfaces is particularly high in terms of the required quality. At the same time, meeting these high standards is often difficult, as it presents the necessary measurement technology with special challenges. In this paper, several measurement methods are shown in order to examine and compare new types of nano-surfaces for contacting for their quality, not only in nano-scale but in large-scale without the need of high resolution methods as SEM.

Combustion processes are characterized by some parameters, including spectroscopic ones. Therefore, it is proposed to use the methods of applied optical spectroscopy to solve the task of diagnosing a combustion process of gaseous hydrocarbon fuel. In this case, the control device is a spectral–selective device that scans optical radiation as a signal carrying spectroscopic information about the combustion process. It can replace most of the control – measuring equipment located at the place of measuring. This device executes spectral measurements in specified areas of the optical range using a set of narrowband interference optical filters tuned to the specific wavelengths. The modernity of the device is confirmed by the Russian Federation patent. In this research, an installation was developed, which includes a burner and a gas supply system. An analysis of the spectroscopic informative properties in the emission spectrum of the flame arising from the combustion of hydrocarbon fuel was carried out. The experiment was accomplished by using the Ocean Optics USB2000 + spectrometer. The results of this experiment provided comprehensive information on the wavelength values of the optical filters are needed. These filters are part of the spectral–selective diagnostic device. Then a prototype of the spectral selective device for a combustion diagnostic was developed and assembled. In this paper, the results of experimental research of this device and a comparative analysis with the Ocean Optics USB2000 + spectrometer within the case of solving the problem of gaseous hydrocarbon fuel combustion diagnostics are also provided.

The fast transmission of signals around the globe is fundamental to the flow of information for our society. A long-haul transmission certainly represents one of the key advancements that shaped modern ways of communicating and offers a nearly instant access to any available data or a latest information. However, fiber-optic transmission typically suffers from a variety of physical impairments that degrade the signal quality, thus imposing limits on both, the achievable transmission capacity and data reach. Of particular concerns are stochastic fiber impairments, primarily represented by polarization mode dispersion (PMD). The PMD originates from a random birefringence caused by imperfect fiber circularity and other, both internal and external, effects, basically completely re-defining the light polarization state of output signal compared to its initial counterpart. The PMD is particularly critical as it restricts operation of fiber-optic links running at speeds higher than 10 Gbps. This, in turn, hinders fiber link re-adaption towards higher transmission bit rates in future, however. In this context, both in-line link monitoring and testing of PMD-based effects is of great importance within the recently used optical fiber links. However, polarization-based effects are also very sensitive to the environmental changes, substantially degrading transmitted optical signals and reducing link quality. In this work, we provide experimental characterization for PMD-based propagation effects in optical fibers influenced by wind gusts. The investigation was performed on commercially used fiber-optic link that runs through optical power ground wire cables. The 111-km-long optical link under study comprised installed optical fibers with available 88 channels. Here, we monitored environmental changes caused by wind conditions over several consecutive days with a 60 second time frame and sensed PMD impact on the link performance. Here, differential group delay (DGD) was chosen to be a key parameter, enabling for sensitive characterization of wind related link changes. Measured maximum DGD’s were 4 and 10 ps for wind speeds up to 5 and 20 m/s, respectively. In addition, experimentally measured data were used in numerical model to assess the optical link quality. For a low wind condition, we observed negligible quality degradation in the optical link, considering transmission bit rates of 10, 40, and 100 Gbps. Conversely, in case of strong wind condition, the optical link maintained a reliable operation only for established 10 Gbps, while significant link degradation was observed for bit rates of 40 and 100 Gbps. Our work shows promising way to effectively sense and monitor undesired environmental variations and their impact on polarization-based fiber link propagation effects, which in turn, can allow an instant link quality evaluation.

This work is devoted to investigation of the temperature influence on the spectral and luminescent properties of borate glass ceramics obtained by high-temperature heat treatment of the initial glass containing chromium oxide. The luminescence and absorption spectra are obtained for samples with different concentrations of antimony oxide, which plays the role of a reducing agent, during heating and subsequent cooling. The dependence of the luminescence intensity on temperature is established. The possibility of using the materials under study as luminescent temperature sensors is considered.

Article summarizes past and continuous development, and especially current state of Czech national research infrastructure for Clock Network Services and future development plans. The focus is on used transmission means and stabilization techniques, available and planned wavelength bands and also plans for geographic extensions.

An acoustooptic modulator is considered as an element of a system for processing signals in the radio and optical range with a lattice-like structure. The importance of spectral measurements of the optical range in science and technology is noted. A method is proposed for measuring the spectra of optical signals with an idealized spectral device based on an acoustooptic tunable filter. A method for measuring the spectrum of an optical signal with a spectral device based on an acoustooptic tunable filter with a frequency-hopping change in the frequency of the control signal is presented. The mathematical model of the optical system is described as a bilinear spectral transformation of acoustooptical interaction. An exhaustive characteristic of the optical spectrum analyzer is calculated – its complex instrumental function.

This work reports the performance improvement of the CZTSSe solar cell by using a back surface field (BSF) layer between the back contact and absorber layer. Firstly, a cell model with Cadmium (Cd) free buffer structure (Mo/CZTSSe/Zn(O, S)/ZnO/ITO) is developed using SCAPS-1D software. To improve the performance, thickness and composition ratio of the absorber (CZTSSe) and buffer (Zn(O, S)) layer are optimized through simulations. The efficiency of 14.39% is achieved for a Sulphur content of 40% and 70% in CZT(SxSe1-x)4 and Zn(O1-x Sx) respectively. Further performance improvement is attempted by using a back surface field (BSF) layer between the back contact and the CZTSSe absorber layer. The P⁺-MoSe₂, P⁺ - Si0.75Ge0.25, and SnSe layers are used as BSF layers to investigate their effects on performance improvement. Inclusion of the BSF layer gives further scope for optimization of the absorber layer thickness. It is observed that the use of SnSe as a BSF layer produces maximum power conversion efficiency of 17%. These findings will be helpful for the research community working in the area of high-performance and low-cost CZTSSe based solar cells.

This work is devoted to the study of phase transitions in CsPbBr₃ perovskite nanocrystals nucleated in borogermanate glass. Perovskite nanocrystals are obtained by bulk crystallization in a glass matrix. A series of glass samples with nanocrystals of different sizes is investigated. Upon heating, the temperature dependence of the 1S exciton intensity for the entire series of samples shows the presence of three phase transitions: in the range 130-150, 440-450, and 510-515°C. The first phase transition refers to the transition from a tetragonal to a cubic structure. The last phase transition is associated with the melting of the crystalline phase. The phase transition at 440°С is declared for the first time. Upon cooling, the temperature curve shows the presence of only one phase transition in the region of 330°C, which is associated with the crystallization onset of CsPbBr₃ perovskite nanocrystals in glass matrix.

The paper considers aspects of an experimental research of the inhomogeneity of the spatial distribution of the absolute sensitivity of multielement photodetectors based on CCD and CMOS structures. The relevance of this research is associated with the need to calibrate optical radiation photodetectors in high-precision instruments to achieve specified measurements, recognition or measurement of parameters of objects of observation. Accuracy distributions on the photosensitive matrix working area are obtained, which make it possible to simplify the geometric distortion correction algorithm, improve the calibration scheme, and reduce the load on the digital processor. In this work, the choice is substantiated and a scheme of the installation is proposed for conducting experimental researches of the spread in the sensitivity of the photodetector at the working site. The results obtained in the course of the research can be used in the calibration of multi-element optical photodetectors to take into account the influence of the uniformity of their sensitivity over the site, in measurements during digital image processing.

We investigate an impact of a small particle located on the surface of a fiber resonator on the dynamics of the whispering gallery modes (WGM) circulating near the fiber surface. We consider a single molecule of fibrinogen and bovine serum albumin that is put in contact with the surface of the fiber. We have studied both temporal dynamics of optical pulses propagating at the WGM as well as changes in the spectrum of WGM due to impact of the particle.

To support people’s wayfinding activities in crowded buildings minimizing the risks of contamination this paper proposes a method able to generate landmark route and alert instructions using Visible Light Communication (VLC). The system is composed of several transmitters (ceiling luminaries) which send the map information, alerts and the path messages required to wayfinding. The system informs the users, in real time, not only of the best route to the desired destination, through a route without clusters of users, but also of crowded places. An architecture based on a mesh cellular hybrid structure was used. Data from the sender is encoded, modulated and converted into light signals emitted by the transmitters. Tetra-chromatic white sources are used providing a different data channel for each chip. The modulated light signal, containing the ID and the 3D geographical position of the transmitter and wayfinding information, is received by a SiC optical sensor with light filtering and demultiplexing properties. Each luminaire for downlink transmission is equipped with one two type of controllers: mesh controller and cellular controllers do forward messages to other devices in the vicinity or to the central manager services. The light signals emitted by the LEDs are interpreted directly by the receivers of the positioned users. Bidirectional communication is tested. The effect of the location of the Access Points (APs) is evaluated and a 3D model for the cellular network is analyzed. In order to convert the floorplan to a 3D geometry, a tandem of layers in an orthogonal topology is used, and a 3D localization design, demonstrated by a prototype implementation, is presented. Uplink transmission is implemented, and the 3D best route to navigate through venue is calculated. Buddy wayfinding services are also considered. The results showed that the dynamic VLC navigation system enables to determine the position of a mobile target inside the network, to infer the travel direction along the time, to interact with received information and to optimize the route towards a static or dynamic destination, avoiding the threat of contamination in crowded regions.

The article discusses the possibility of using a two-position onboard optical-location system for detecting, classifying and determining the coordinates of the trajectory of objects in the video stream installed on the small aircraft. Every year the requirements for new monitoring systems are becoming more stringent. The data obtained from a single, albeit highquality, optical sensor can no longer meet the assigned tasks, such as performing search and rescue operations in remote areas, as well as solving problems of finding people in disaster zones. and environmental disasters in a complex noise environment. The system considered in the article includes optical-location sensors, each of which is capable of forming a high-resolution image and classifying the observed objects, as well as, when used together using stereo vision methods, to obtain estimates of the coordinates of the object's trajectory. observed objects. It is shown that combining information in an optical location system allows detecting, classifying and determining the parameters of motion of objects, including people and animals. The article presents the operating modes of the system, and the corresponding restrictions on the conditions for its effective operation.

Fiber vibration sensors have shown great performance in structural safety monitoring. In this work, a fiber vibration sensor with an ultra-broadband frequency response based on single-mode-few-mode fiber coupler (SFC) was demonstrated. The SFC was fabricated with a pre-stretched single- mode fiber (SMF) and a few-mode fiber (FMF) by weak fusion technology. The proposed vibration sensor has an ultra-broadband sensing frequency response span from infrasound (Hz) to ultrasonic (MHz) with high linearity of ≈1 and good fidelity. What is more, the highest signal-to-noise ratio (SNR) of single- and dual-frequency vibration detection are separately ~108 dB and ~105 dB and damped vibration signals with different frequencies can be detected as well. Additionally, the sensor has highly stable cross-sensitivity at low temperature, which can be applied in structural health monitoring and environmental assessment.

The development of powerful sources with wide spectral coverage is important for many sensing applications. In this paper, various superfluorescent fiber sources (SFS) at 1μm Wavelength using Ytterbium doped (Yb-doped) fiber is studied. Different configurations such as single pass forward (SPF), single pass backward (SPB), double pass forward (DPF), double pass backward (DPB), are compered in terms of spectral bandwidth, power, central wavelength stability and power stability. Double-pass bi-directional sources are employed using loop mirrors. For all cases, maximum power is compared at various laser diode power. Mean wavelength stability is measured between temperature of -40/+60°C to assess potential applications.

Mechanical stress is developed in the materials during and after manufacturing of devices. In microelectronics components, like integrated circuits, the stress in the interconnections is a very crucial phenomenon. Consequences are defects, which are more serious with the constantly increasing complexity and miniaturization of the devices. To develop strategies to minimize the stress phenomena, it is essential to analyze the stress morphology. Micro-Raman spectroscopy is an effective technique to measure local patterns with spatial resolution of less than micrometers. Focus of this study is the monitoring of stress induced on blue gallium nitride LEDs after soldering onto copper substrate. Stress values above 1 GPa are observed, which indicate compressive stress, especially in the central area of the LED. The results are discussed in terms of thermal expansion coefficients and soldering process, with the aim to enhance the reliability of the interconnections, optimize the bonding processes and provide crucial data for the improvement of packaging design.

In ITER, polarimetric optical fibre sensors measure the plasma current (0-17 MA) by exploiting the Faraday effect induced state of polarisation (SOP) rotation of a polarised light propagating in the sensing fibre, placed on the outer surface of the ITER vacuum vessel (VV) section. In the discussed here system, the polarisation-OTDR (POTDR) is employed to analyse the SOP rotation and a spun fibre is used as the sensing fibre. The Verdet constant is the proportionality constant between the SOP rotation and the axial magnetic field induced by the current. The presence of unwanted birefringence in the sensing fibre will degrade the measurement accuracy. In this paper, we analyse the effect of the birefringence induced by the fibre bending and twisting together with the effect of the temperature dependence of the Verdet constant. Due to the difficulty in taking measurements in the ITER representative conditions, a simulation approach is developed—using Jones formalism—to show that the performance of the sensing fibre in terms of plasma current measurement can be characterised by the ratio of precursor fibre linear beat length (LB) over its spun period (SP) i.e., LB . Finally, we estimate the minimum required LB/SP ratio of the sensing fibre needed to satisfy the ITER plasma current measurement specifications.

Photoacoustic tomography technology is a new imaging technology based on photoacoustic effect. It has become one of the most important techniques in biomedical imaging field because of its non-invasive, non-ionized and high resolution. The imaging data of photoacoustic imaging is complex. The traditional Nyquist sampling consumes much time and resources. And it requires high equipment. In order to improve the sampling efficiency and reduce the equipment requirements, Compression Sensing (CS) theory has been used to collect photoacoustic data. Compressed Sensing theory can break through the limitation of Nyquist sampling law and reduce the data redundancy greatly so that the desired imaging results can be reconstructed with less time and resources. In this paper, the K-wave simulation toolbox of MATLAB is used to set up the virtual photoacoustic field and collect the photoacoustic signal of blood vessel. The results show that the MATLAB virtual Compressed Sensing photoacoustic tomography simulation platform based on k-wave can achieve high quality photoacoustic tomography with less data. The superiority of Compressed Sensing theory and the high efficiency and stability of k-wave virtual platform are verified. Also, the Compressed Sensing reconstruction algorithm OMP and ROMP are compared in this paper and the result shows that the ROMP algorithm works better.

In turbomachinery, engine vibrations play an essential role, since they may lead to a fast component degradation, lowering the performance and ultimately yielding to fatigue damage. For these reasons, there is a high demand for measurement methods to monitor the behavior of the engine shaft adequately. In this experiment, we characterize the shaft behavior of a turbomachine by measuring the blade tip clearance and by converting it to a shaft displacement. To achieve this goal, we have employed two optical displacement sensors and we have applied the full spectrum technique.

UV radiometers are used in many areas. There are many kinds of UV light sources with different peak wavelength and different wavelength range. The broadband UV radiometers are wildly used due to easy to use and low cost. However, there are some obvious disadvantages for the broadband radiometers. They cannot distinguish the spectral characteristics of UV sources. That will cause the spectral mismatch measurement error for the UV broadband radiometers calibration. Recently, the fiber spectroradiometer plays a more and more important role in this area. The fiber spectroradiometer is more portable and low cost compared to the double grating spectroradiometer. We can obtain the spectral characteristics and any UV irradiance using the fiber spectroradiometer. However, for most fiber spectroradiometers, we cannot use them to replace the UV broadband radiometers for the absolute irradiance measurement. There are four key effects for that. The first one is the stray light. Stray light effect is obvious for the fiber spectroradiometer, especially in the UV wavelength range. The second one is the temperature effect. The third one is the non-linearity effect. The fourth one is the bandwidth effect. This effect will cause the measurement error for the spectral distribution of the UV source. In this paper, we research the four factors that reduce the measurement accuracy of the fiber spectroradiometer in UV wavelength range.

Optical frequency standards based on trapped ions have made great progress over the past decades. In this paper, the design of the optical system for an optical atomic clock based on single 171-ytterbium ion at NIM is proposed. According to the requirements for ionization, cooling, repump, interrogation, and detection, the basic optical system design and frequency stabilization scheme are introduced.

This paper presents the process of creating a gold surface modified by periodic structures deposited by femtosecond laser radiation by two different geometry. The refraction processes of s- and p-polarized light on the gold structured surfaces with the changes in the dielectric permittivity function were studied and compared in this paper. The presence of surface plasmon generation on the rough gold surface in visible region at two frequencies has been established in this work.

Photoacoustic imaging is a new biomedical imaging technology developed in recent years. It has the advantages of high resolution and sensitivity to the functional characteristics of biological tissues. However, whether for photoacoustic tomography or photoacoustic microscopy imaging, the imaging resolution depends on the frequency and bandwidth of the received ultrasonic signal. This leads to a large amount of data being collected under the Nyquist’s law. So storage medium and DSP processor are under unprecedented pressure. The problem of large amount of data is usually solved by using compression. Therefore, the combination of compressed sensing theory and photoacoustic imaging can not only restore images with high quality, but also reduce the amount of data as much as possible. It saves storage space and the time of further data processing. This paper introduces signal sparsity and measurement matrix of compressed sensing theory briefly. The virtual photoacoustic imaging of blood vessels is carried out in the simulation environment constructed by the k-wave toolbox of MATLAB. The collected data are restored by using the gradient projection for sparse reconstruction. The results show that high quality photoacoustic imaging images can be reconstructed while a small amount of data is stored. The performance of the simulation platform is verified. And it is of great significance to solve the problem of high data volume of photoacoustic imaging.