In this work, the effects of direct femtosecond laser nanostructuring on monocrystalline silicon (Si) wafer immersed in liquid environment were studied. Ultrashort laser exposure induced nonequilibrium states in materials triggers the morphology self- organization driven by excited electromagnetic and hydrodynamic processes, which ultimately give rise to the formation of regular nanogratings with different periodicity (Λ1=250 nm to 300 nm, Λ2=70±10 nm) and randomly arranged spike structures. The type of the nanotextures can be controlled by varying the laser fluence and polarization distribution of the incident laser beam studied for the cases of linearly/circularly polarized Gaussian laser beams as well as azimuthally polarized cylindrical vector beam. Through laser-induced interface chemical reactions stimulated by adding the appropriate salt/acid/molecular precursors in the process of liquid-phase Si texturing, it becomes possible to functionalize the obtained nanotextures with mono- and multi-metallic nanoparticels and/or photoluminescent chemosensing molecular probes. Adjusting laser processing parameters and component functionalizing solutions has providing a flexible approach for large-scale manufacturing that can be realized for diverse applications such as light harvesting, chemosensing, optical detection, heterogeneous catalysis and microfluidics.
In this paper an on-chip device capable of wavelength-selective generation of vortex beams is demonstrated. The device is realized by integrating a spiral phase-plate onto a MEMS tunable Fabry-Perot filter. This vortex-MEMS filter, being capable of functioning simultaneously in wavelength and orbital angular momentum (OAM) domains at around 1550 nm, is considered as a compact, robust and cost-effective solution for simultaneous OAM- and WDM optical communications. Experimental spectra for azimuthal orders 1, 2 and 3 show OAM state purity >92% across 30 nm wavelength range. A demonstration of multi-channel transmission is carried out as a proof of concept.
The phase of light propagating through a bent optical fibre is shown to depend on the refractive index of the medium
surrounding the fibre cladding when there is resonance coupling between the guided core mode and cladding modes.
This shifts the spectral maxima in the bent fibre-optic Fabry-Perot interferometer. The highest phase and spectral
sensitivities achieved with this interferometer configuration are 0,71 and 0,077, respectively, and enable changes in the
refractive index of the ambient medium down to 5·10-6 to be detected. This makes the proposed approach potentially
attractive for producing highly stable, precision refractive index sensors capable of solving a wide range of liquid
refractometry problems.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.