We demonstrate a direct laser writing setup combining 405 nm multi-photon lithography with 4Pi excitation enabled by a spherical reflector (SR) refocussing the transmitted excitation. The SR provides a simplified implementation of the 4Pi geometry, avoiding the need for an additional objective and its interferometrically stabilised excitation beam path, while also recycling the beam power. The reflected beam position is measured by imaging the reflected beam and is controlled by a feedback loop to 10nm in all three dimensions. Using this instrument, the fabrication of sinusoidally modulated nanowires and helicoids with sub-100nm near-isotropic cross-section is demonstrated.

We fabricate all-inorganic, high refractive index optics, including metalenses, waveguides, and diffractive optical elements via nanoimprint lithography with TiO2 nanoparticle dispersion inks and report full-wafer fabrication of visible wavelength metalenses with absolute focusing efficiencies greater than 80% (>95% of design efficiency). 3-D metal oxide log-piles are possible via direct NIL using sequential imprint, planarization, imprint cycles followed by removal of the sacrificial planarization layers. 3-D metal log-piles are possible via metallization of imprinted 3-D sacrificial templates. Several examples will be discussed.

The smaller the diameter of an endoscope, the greater its potential for minimally invasive surgical treatments. In conventional, flexible (fiber-based) endoscopes with small diameters (<200 µm), imaging is severely limited by the number of fiber cores. Due to this limitation, the image is pixelated. In this work, an engineering approach is used to increase the number of pixels by spectral multiplexing. However, this requires very small color-splitting optical systems at the distal end of the endoscope, i.e., at the body-facing end of the fiber. Such small dispersive optical systems are practically impossible to produce directly on the fiber using conventional techniques. Therefore, the idea is implemented using 3D-printed micro-optics. Preliminary work has shown that multiphoton lithography (fs DLW) is capable of producing imaging and color splitting systems on this size scale. We present the optical design, fabrication and test of a fiber core multiplexing endoscope with a diameter of only 160 µm. Single-shot resolution enhancement is demonstrated by imaging of a USAF test chart and biological samples.

This presentation focuses on examples of devices and components to be used in actual biological and biomedical applications and manufactured in larger quantities. Specifically, we discuss additive manufacturing (full 3D and 2.5D grayscale modes) based on 2PP technology, which allows features of 100nm-150nm and surface roughness of 10-20 nm – sufficient for optical quality components. In addition, the printing volume allows parts of up to 50x50x22 mm3 and thus broader range of possible designs. Here we demonstrate two system examples: (1) high performance (NA=0.6, FOV=200microns, OD = 3.0 mm) hybrid endoscopic microscope objective for 2-photon imaging and diagnostics and (2) image mapping spectrometer for cell signaling in SPIM (Selective Plane Illumination Microscopy) configuration. In both cases we discuss performance of manufactured components and design strategy to optimize both printing time and component/system quality. Presented prototypes demonstrate high level of integration, compact dimensions and design flexibility. Results include high resolution imaging performance (miniature endo-microscopic objective) and snapshot spectral imaging capabilities in cell signaling.

We introduce a compact attachment for microscope objectives that allows for the conversion of conventional fluorescence microscopes into Airy light-sheet microscopes. The attachment includes a one-dimensional Airy beam generator, which comprises a gradient-index collimator and a 3D nano-printed cubic phase-plate, realized through two-photon polymerization 3D nano-printing and a two-step writing process that guarantees an optical-quality surface for the phase plate. The micro-optical unit is affixed to a mechanical holder equipped with micro-stages, thereby facilitating the unit's integration into commercial microscopes. The implementation and imaging performance of this system and its fundamental imaging characteristics are discussed, with findings based on diverse samples.

3D µ-printing is a versatile technology with huge potential for fabricating high-quality microstructures. However, most structures initially deviate from their designed dimensions due to photo resin properties and/or optical aberrations. We present a deep learning approach to predict and subsequently correct these optical aberrations in high numerical aperture systems, commonly employed in multi-photon lithography. The neural network identifies and calculates corrections for prominent aberrations and allows for easy scaling to arbitrary laser wavelengths. We also demonstrate our first steps of a machine learning approach that allows pre-compensation of microstructures without several (intensive) iterative correction prints.

The use of 3D printed micro-optical components has enabled the miniaturization of various optical systems, including those based on single photon sources. However, in order to enhance their usability and performance, it is crucial to gain insights into the physical effects influencing these systems via computational approaches. As there is no universal numerical method which can be efficiently applied in all cases, combining different techniques becomes essential to reduce modeling and simulation effort. In this work, we investigate the integration of diverse numerical techniques to simulate and analyze optical systems consisting of single photon sources and 3D printed micro-optical components. By leveraging these tools, we primarily focus in evaluating the impact of different far-field spatial distributions and the underlying physical phenomena on the overall performance of a compound micro-optical system via the direct evaluation of a fiber in-coupling efficiency integral expression.

Hollow-core waveguides represent a promising type of on-chip waveguide, enabling strong light-matter interactions for guiding light directly in the medium of interest. Hollow-core waveguides are very established in fiber optics, while they receive much less attention in on-chip photonics. Here, we will show how 3D nanoprinting is used to transfer hollow-core waveguide concepts from fiber optics to on-chip photonics. Two main types of nanoprinted waveguides are discussed, yielding a high-power fraction in the core and lateral access to the core region. We will explain applications of these waveguides in gas- and water-based spectroscopy, nanoparticle tracking analysis and optical fiber interconnection.

Manufacturing of 3D-printed micro optics using two photon lithography (2PL) has been advancing rapidly over the last decade, enabling production of high-performance micro optics. Among many more, 3D-printed miniaturized sensors, imaging optics, OCT systems, spectrometers and optical tweezers appear to be promising for application in the biomedical field. Here, immersion of optical systems into aqueous solutions is required regularly, hence capsulation for protection of the optical system's interior is required. Yet, specific properties of the 2PL fabrication process render capsulation of fabricated optics a delicate task. In this talk, we outline a wholistic design strategy for 3D-printed immersion micro optics. The optical design and the mechanical manufacturing process are addressed, as well as approaches to combine metrology and simulation techniques for accurate assessment and performance optimization of manufactured systems. The feasibility of the proposed concept is experimentally validated. We discuss current limitations and evaluate the future potential of 3D-printed immersion micro optics.

Additive fabrication, in particular direct-laser writing (DLW) combined with two-photon polymerization (TPP), stands out as an innovative tool for creating intricate 3D photonic components. However, the long fabrication time associated with DLW-TPP restricts large-scale implementations. Here, we introduce an adaptative lithography strategy, i.e. flash-TPP, combining one- (OPP) and TPP, while adjusting the resolution of the different sections of the photonic circuit, reducing the printing time by up to 90% compared to TPP-only. Via flash-TPP, we demonstrate the fabrication of polymer-cladded single-mode photonic waveguides and adiabatic splitters, with low 1.3 dB/mm (0.26 dB) propagation (injection) losses and record optical coupling losses of 0.06 dB with very symmetric (3.4 %) splitting ratios for adiabatic couplers. The scalability of output ports here addressed can only be achieved by using the three spatial dimensions, which is challenging in 2D.

Meta-Fibers, which incorporate 3D-printed Metalens into optical fiber facets, are versatile technology with applications in imaging, optical trapping, and electromagnetic wave manipulation. Single-Mode Fiber (SMF) stands out for its defined output, but its limited mode field diameter poses a challenge, often requiring fusion splicing with Multi-Mode Fiber (MMF) or a 3D-printed structure to expand SMF's usable cross-section. However, these methods are complex and may damage the Meta-Fiber. This study introduces an alternative, replacing SMF with Thermally Expanded Core (TEC) fiber, featuring a significantly larger mode field diameter. This approach enables optical trapping and imaging via 3D laser-printed ultra-high numerical aperture metalens into TEC fibers, functioning effectively in diverse environments. The findings expand Meta-Fiber applications, providing an efficient, robust, and scalable solution for optical wavefront manipulation, highlighting the potential of TEC fibers in optics and photonics technology.

Fabrication of glass with complex geometric structures by digital additive manufacturing (3D printing) presents a paradigm shift in glass design and molding processes. Till now, 3D printing glasses have suffered from limited printed glass materials and the low resolution of particle-based or fused glass technologies. Herein, a high-resolution 3D printing of transparent nanoporous glass is presented, by the combination of transparent photo-curable sol-gel printing compositions and vat photopolymerization technology (Digital Light Processing, DLP). Multi-component transparent glass, including binary, ternary, and quaternary oxide nanoporous glass objects with complex shapes, high spatial resolutions, and multi-oxide chemical compositions are fabricated, by DLP printing and subsequent sintering process. We successfully demonstrated the photoluminescence and hydrophobic modification of 3D printed glass objectives. This work extends the scope of 3D printing to transparent nanoporous glasses with complex geometry and facile functionalization, making them available for a wide range of applications.

Metal additive manufacturing is currently experiencing strong growth in the industry. Until recently, it remained confined to small dimensions, a consequence of the limits imposed by the technologies used (mainly PBF (Powder Bed Fusion) technology). Today, suppliers offer large PBF machines using numerous lasers to ensure sufficient manufacturing speeds. Furthermore, another large-scale offer is based on the use of DED (Directed Energy Deposition) processes which use an energy source (for example Laser) to melt a deposited filler material to form the volume layer after layer. of the room. IREPA LASER has therefore developed a new technology capable of manufacturing or repairing XXL parts (up to 5 meters in length and weigh up to 5 tonnes). This technology is based on a head for depositing one or more molten metal wires using a high-power laser (10kW). This presentation will be an opportunity to take stock of the evolution of additive manufacturing technologies, and to present the latest results obtained in the field of DED, but also to show that the laser has become essential in manufacturing industries.

3D laser nanoprinting based on multi-photon absorption (or multi-step absorption) has become an established commercially available and widespread technology. Here, we focus on recent progress concerning increasing print speed, improving the accessible spatial resolution beyond the diffraction limit, increasing the palette of available materials, and reducing instrument cost.