This PDF file contains the front matter associated with SPIE Proceedings Volume 10544, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Short DNA strands can be used as robust and versatile templates to produce plasmonic nanostructures with a fully controlled chemical environment. They allow the parallel production of millions of copies of gold particle dimers linked by a single DNA strand with gaps that can be controlled at the nanometer scale (M. P. Busson et al, Nano Lett. 11, 5060 (2011)). In particular, fluorescent dye molecules can be easily introduced in such plasmonic antennas at the position where optical fields are strongly enhanced and confined (M. P. Busson et al, Nat. Commun. 3, 962 (2012)). In practice, the efficiency of DNA-templated optical antennas can be optimized to enhance the excitation and emission rates of single fluorescent molecules by two orders of magnitude while reaching quantum yields as high as 70 % (S. Bidault et al, ACS Nano 10, 4806 (2016)). Furthermore, by introducing two dye molecules that act as a FRET (Förster resonant energy transfer) pair, we show how field confinement in plasmonic antennas allows the modulation of non-radiative energy transfer processes (S. Bidault et al, ACS Photonics 3, 895 (2016)). The flexibility of DNA-based self-assembly also means that the morphology of the produced nanostructures can be modulated in-situ. For example, we show how the gap between two 40 nm gold particles can be tuned, and monitored spectroscopically, between 20 nm and ~1 nm by modifying the ionic strength (L. Lermusiaux et al, ACS Nano 9, 978 (2015)), opening perspectives for the active tuning of DNA-templated plasmonic nanoantennas.

Plasmonic metasurfaces have been receiving tremendous attention because of their extraordinary optical properties. However, time consuming and expensive fabrication methods such as electron beam lithography or focused ion beam (FIB) hinder its commercial application to sensors, color filters, and photovoltaic solar cells. In this study, we demonstrate that metal-dielectric-metal reflective meta-surfaces can be fabricated in a simple and low-cost way using a one-step covalent bonding-assisted nanotransfer process. We prepared various sizes of nanoscale hole-type patterned silicon master, because the represented color depends on the hole size and period. Ag and SiO₂ were deposited onto the replicated polymer stamp from the silicon master, then transferred onto the Al-deposited glass wafer. Strong covalent bonds were formed rapidly between oxygen from the SiO₂ and Si from the adhesive. In this way, we easily fabricated metasurfaces using a one-step nanotransfer process. Finally, finite-difference time-domain method (FDTD) simulation was carried out whose outcome matched experimental results, thus verifying our approach.

We show that a multimode fiber which can be either a graded index fiber or fiber bundle can be used to deliver shaped light to build useful complex parts in areas difficult or impossible to reach with conventional manufacturing tools. We will show complex objects of micrometer scale that are made by additive manufacturing with either a single photon or a 2 photon process. The large effective core area of the multimode fiber allows two orders of magnitude higher pulsed energy transfer while maintaining a spatial and temporal diffraction limit. This enable both subtractive and additive manufacturing.

The exponential demand on the internet is producing a capacity crunch in legacy short haul communication networks based on multimode fibre, and is foreshadowed to do the same for long haul single mode fibre networks. Femtosecond lasers have been used to produce a range of compact lightwave circuits that are compatible with optical fibres. These include 3D lightwave chips that offer mode selectivity. Recent developments in plug-and-play devices produced by the fs laser direct-write technique have enabled the modes of few mode fibre (FMF) to be individually addressed with high fidelity (20dB mode extinction). 10G has also been demonstrated over 2 kms of conventional multimode fibre (OM1 and OM2) with fs laser written photonics. As a result, this platform can extend the service life of existing multimode fibre networks and enable next generation networks exploiting mode division multiplexing.

Fabricating photonic structures directly on the edge of an optical fiber opens opportunities in telecommunication, sensing, lab-on-fiber and as a replacement for the conventional free-space optics. The main advantages are long-term stability, compact size, ease of use, and the scalability. We report a novel method to fabricate 3D free-form photonic structures directly on the optical fiber using Nanoimprint Lithography. A series of “photonic-on-a-fiber” devices are presented including; high-refractive index Fresnel lensed fiber, vortex phase plate on a fiber, beam shaper, and a diffractive beam splitter on a fiber. Innovative fiber photonics devices enable cost-effective and simple wavefront manipulation.

This paper describes the low-cost, scalable fabrication of 2D metasurface LWIR broadband polarized emitter/absorber. A Frequency Selective Surface (FSS) type design consisting of dipole antenna elements is designed for resonance in the 7.5-13 μm band. Frequency-domain Finite Element Method (FEM) is used to optimize the design with ellipsometrically measured properties. The design is synthesized to be broadband by creating a multiple cavities and by hybridizing the dipole modes with phonon resonances in a germanium/silica dielectric which separates metallic elements from a continuous ground plane. While IR metasurfaces can be readily realized using direct-write nanofabrication techniques such as E-Beam Lithography, or Focus-Ion Beam milling, or two-photon lithography, these technologies are cost-prohibitive for large areas. This paper explores the Microsphere Photolithography (MPL) technique to fabricate these devices. MPL uses arrays of self-assembled microspheres as optical elements, with each sphere focusing flood illumination to a sub-wavelength photonic jet in the photoresist. Because the illumination can be controlled over larger scales (several μm resolutions) using a conventional mask, the technique facilitates very low cost hierarchical patterning with sub-400 nm feature sizes. The paper demonstrates the fabrication of metasurfaces over 15 cm² and are measured using FTIR and imaged with a thermal camera.

We have previously introduced a femtosecond laser micromachining-based scheme for the fabrication of anisotropic waveguides and isotropic Bragg reflection gratings in lithium niobate for application in future integrated-optic spatial light modulators. In this paper, we depict progress in fabrication and characterization of anisotropic Bragg reflection gratings fabricated in lithium niobate via Type I femtosecond laser-based permittivity modulation. We furthermore depict an electromagnetic analysis of such multilayer grating structures based around coupled-wave theory for thick holographic gratings.

Direct Laser Writing techniques like two-photon-polymerization or UV-lithography have become common tools for the micro- and nanofabrication of precise devices like photonic crystals. A decrease in the size of structures of special devices requires a significant better resolution of the laser beam system that can be determined by using different photoinitiators or a second depletion laser for STED-lithography.

However, besides the optical limits for the resolution of the laser system due to diffraction effects, the positioning systems for the laser beam or the sample stage lead to further imprecisenesses. To benefit from the high resolution techniques for the structuring process, the need for highly accurate positioning systems has dramatically grown during the last years. A combination of lithographic techniques with a nanopositioning and nanomeasuring machine NMM-1, developed at the TU Ilmenau, enables high precision structuring capability in an extended range. The large positioning volume of 25mm x 25mm x 5mm with a resolution in the sub-nanometer range is a good condition for ultra precision manufacturing with large area 3D-Laser-Lithography. Advantages and disadvantages as well as further developments of the NMM-1 system will be discussed related to current developments in the laser beam and nanopositioning system optimization. Part of the further development is an analysis of the implementability of additional ultra precise rotational systems in the NMM-1 for the unlimited addressability perpendicular to the surface of a hemisphere as key strategy for multiaxial nanopositioning and nanofabrication systems.

This paper discusses refractive index (n) measurement capabilities of interferometers based on micro-cavities of various diameters (d = 50 and 60 μm) fabricated in optical fibers by a femtosecond laser. In comparison to previously presented structures, the reported sensor operates in the near-infrared spectral range. Bottom of the cavity intersected the fiber’s core (5.2 μm in diameter), which induced the Mach-Zehnder interferometer effect. After filling the cavity, a set of minima can be observed in the transmission spectrum, and they shift in wavelength with a change in n. The fabricated sensors exhibit high and linear sensitivity and can measure sub-nanoliter volumes of liquids, what make this sensor perfect for various diagnostic medical or biochemical applications.

A sensitive bolometric detector for visible and infrared wavelengths based on a novel assembly principle of a graphene monolayer on a nano/micro SiN membrane is realised. The basic operating principle of the optical detector relies on the absorption of electromagnetic radiation in the graphene and creation of a strong thermal gradient, rT, which is detected via the Seebeck effect: Voltage = S x ∇rT, where S is the Seebeck coefficient of graphene. A simple lithography-free deposition of two metal contacts with different electron work functions: Pd (by sputtering) and Ag (by jet printing and annealing) was used. Sensitivity of the bolometer was the same ~1:1 mV/mW at 1030 and 515 nm wavelengths.

We report here a study on extrinsic propagation losses in silicon slot photonic crystal waveguides. This specific geometry of hollow slow light waveguides offers an exceptional platform for the integration of active materials on silicon because of the strong light/matter overlap and the flexibility in dispersion engineering at moderate group indices that it allows. However, the exploitation of slow modes simultaneously increases the propagation losses as it has been already demonstrated in non-slotted waveguides. We present in this work an experimental study of the influence of the e-beam and etching fabrication steps of photonic structures on the level of propagation losses in both the fast and slow wave propagation regimes and for the first time in slotted configuration. We have studied the influences from the e-beam lithography exposure method and dose control for periodic pattern writing, and measured the level of propagation losses as a function of the group index of the excited Bloch modes. The collected results have revealed a strong influence of the stages of fabrication of the structures and opened the way to a possible technological optimization of the propagation losses of slotted slow light waveguides. Among the points to be remarked, we have observed that the lithographic writing of the slot in a truncated way could lead to a reduction of propagation losses in the light propagation regime with a group index greater than 15. Our qualitative interpretation of these results is that by imposing certain constraints on the scanning of the electron beam, we induce a modification of the auto-correlation function which characterizes the fabrication roughness of the edges of the slot of the waveguides. Additional approaches will be presented, opening the optimization of slotted waveguide for diverse applications.

The direct write of photonic elements onto substrates presents opportunities for rapid prototyping and novel sensing architectures in domains inaccessible to traditional lithography. In particular, focussed electron beam induced deposition (FEBID) of platinum is a convenient technology for such direct-write applications with the advantage of relatively controlled deposition parameters and sub-10 nm resolution. One issue for FEBID of platinum is that the precursor gas contains a relatively high carbon content, which in turn leads to carbonaceous deposits in the final structure. Here we explore the creation of plasmonic nanoantennae using FEBID platinum. We compare as-deposited and annealed antenna with heights of 40 nm and 56 nm, showing the effect of annealing on the carbon concentration and hence the optical properties. These results are compared with modelling using Mie scattering theory. Our results show that FEBID platinum is a useful material for the direct-write of plasmonic nanoantenna.

Microsphere Photolithography (MPL) uses an array of self-assembled microspheres as optical elements. Flood illumination is focused to a photonic jet by each microsphere. Simulation and experiments show that photonic jet can be as small as λ/3, with collimation of more than a wavelength. This provides significant potential for pattern transfer of sub-micron patterns over large-areas and offers an inexpensive alternative to direct-write techniques such as e-beam lithography or two-photon absorption. This has applications such as SERS and SEIRA templates as well as metasurfaces to control radiation heat transfer. For these applications, the underlying substrate is important for the device performance and often presents a considerable index-contrast with the photoresist. The substrate significantly affects the behavior of the photonic jet and changes the necessary dose, minimum feature size, and morphology of the exposed area. This paper explores the effects of the substrate on the process. Numerical models using commercial (HFSS) frequency-domain Finite Element Method (FEM) is used to simulate the interaction of light with the microsphere/photoresist/substrate. The distribution of the electric field is used to predict the exposure curve for the process. In general, metals and high index materials cause significant standing waves in the photoresist which modifies the hole morphology and ultimate feature size. These predictions are compared to i-line illuminated experiments with SEM measured hole dimensions for aluminum, germanium, and glass substrates. The objective of the paper is to establish design rules for the process which can be incorporated into the device design.

Diamond turning is a key technology of ultra-precision machining and it is commonly used for the manufacturing of prototypes or mold inserts in growth markets of the photonic industries. A novel method for surface adaptive fast axis ultra-precision turning will be introduced in this paper. With this new approach, it will be possible to incorporate surface properties and machine dynamics for every kind of surface. In a completely digitalized control chain the CNC functionality is transferred from a classical online algorithm to an high density multicore offline operation where set point profiles for each axis are transferred with up to 10.000 Pt/s directly to the servo drive. To adapt the properties of the surface and the machine dynamics all profiles are analyzed in advance to identify critical spots and adapt the set points profiles of all axis to maximize surface quality. To prove the proposed setup an LED headlight surface will be generated and optimized within this paper.

Applying a technique borrowed from super-resolution microscopy to photolithography, we achieve critical dimensions well below the diffraction limit. Exposing photoresist in the far-field, over a broad area, we can demonstrate dimensions as small as λ/7. In this paper, we show that conventional i-line photoresists exposed with this technique, along with modified processing, are capable of supporting features as small as 50 nm, and possibly smaller. We consider the necessary requirements to achieve sub-diffraction dimensions, detail a simple model for photoresist development, and show its use in predicting the minimum attainable feature size. Finally, we characterize two commercial photoresists, and compare the resulting features to those of the model.

We fabricated transmissive optical diffusers with a randomized concavo-convex surface that was designed to control the irradiation distribution and can be fabricated easily. The diffusers were molded from acrylic using the mold cores machined by ultraprecision cutting or milling. Less stray light was observed from the diffuser molded with the cutting core compared with the milling core. As the Fourier optics simulation was consistent with the measured distribution, it was beneficial for the design evaluation of diffusers. Furthermore, we molded a Penrose-tiling micro-lens-array to generate uniform light distribution without random displacement of each lens. The measurement results showed the feasibility of the Penrosetiling micro-lens-array as a diffuser.

Here we present a new rapid prototyped PZT MEMS actuator for potential 2D scanning endoscopic application. The proposed 6.1 mm x 7.1 mm x 5 μm thick film PZT push-pull actuator made by directly deposited on a thin 100 μm thick stainless steel substrate by using an aerosol deposition (AD) method. The actuator features a stable linear 2D vibration using 1-D actuation. Initial fabrication results, electrical impedance, mechanical will be presented and discussed.

Optical three-dimensional printing (O3DP) have become an advanced and widespread technology for the realization of 3D computer aided models (CAD) to free-form objects. It has evolved to desktop stereolithographic (SLA) devices allowing rapid, accurate and high spatial resolution prototyping out of photoreactive resins. Most of commercially available resins are not cheap and often of unknown chemical ingredients, which limits their wider applicability. Recent advances have shown that renewable raw materials can be applied for preparation of polymers. For example, glycerol, the by-product of biodiesel refining, is a promising candidate which can be used as monomer in the synthesis of bio-based resins as it is or after chemical modification [1]. The primary substance for the photosensitive material was chosen glycerol diglycidyl ether (GDGE) [2]. The following composition was: GDGE, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (30 mol %), radical (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) and cationic (diphenyliodonium hexafluorophosphate) photoinitiators and N-vinylcarbazole as an additive. Autodesk’s open source 3D optical printer Ember (AutoDesk) employing 405 nm light was implemented for dynamic projection lithography (DPL). It allowed selective photopolymerization on demand, later followed by characterization of various photosensitive materials. The bio-based resin was compared to standard materials: Formlabs Clear and Autodesk PR48. It turned out, that the resin had much longer curing time (>10 min for a single layer). Despite this fact, fine structural features were formed and their morphology was characterized using optical profilometer and scanning electron microscopy. It was assessed, that by increasing energy dose, higher structures were acquired and this dependency is linear, thus enabling tabletop graytone lithography out of renewable bioresins.

Most common colors in our world as we see them, for example, in crystals, pigments, metals and salt solutions are the result from light scattering properties of electrons in atoms and molecules. Nevertheless, colors can also result from light interference effects, which are of great importance in the life of organisms. The structural colors of living organisms, e.g., the wings of some birds, insects and butteries, are often more intense and almost angle-independent. Understanding this specific color formation is of great interest for biology and for engineered materials with a broad range of biomimetic real world applications due to forgoing of toxic dyes and pigments. Therefore, the generation of artificial color formation with lithographic methods offers many advantages not available in coated multilayer systems because it avoids multiple complex fabrication steps.

In the present work, we report an effortless fabrication method to generate structural coloration based on microand nano-structures using 3d-laser writing technique. The uniform micro- and nano-structures were produced in a thin polymer film with an refractive index of 1.51. The single structures are aligned in an array to create a blue color field. The identification of the influence of the structures on the artificial color formation was performed using scanning electron microscopy. The optical properties of the blue color was analyzed via an angle-resolved spectrometer.

Electromagnetic metasurfaces allow realization of various photonic functionalities using sub-wavelength thick layers of artificially structured material. Recently, metasurfaces consisting of three-dimensional metallic inclusions arranged into two-dimensional periodic arrays were proposed as a way to realize metasurfaces that have no ground plane and are optically transparent in a wide spectral range. However, practical patterning of such structures is beyond the reach of traditional planar patterning techniques. To address this challenge, we have employed femtosecond direct laser write (DLW) technique combined with simple metallization process. Here, we report fabrication and properties of functional metasurfaces consisting of metallic helices and vertical split-ring resonators that can be used as perfect absorbers and polarization converters. In accordance with theoretical predictions, our samples exhibit perfect absorption resonances tunable in the wavelength range of 4.5 − 9.2 μm by scaling the unit cell size. Perfect absorber structures exhibit polarization and incidence angle-invariant operation with measured absorbance in excess of 0.85 for incidence angles up to 30°. Similar structures may find applications innarrow-band infra-red detectors and emitters, spectral filters, and be combined into multi-functional, multi-layered structures.

Two-photon laser lithography has become one of the most promising additive manufacturing techniques on the micron scale and is applied, e.g., in fields of micro-optics and -robotics as well as optical and mechanical metamaterials. Here, we report on the feasibility, limits and general benefits of this method to fabricate material measures for the calibration of industrial optical topography measuring devices. Since calibration procedures are essential in the scientific and industrial application of those measuring instruments, appropriate material measures are highly required. In contrast to traditional manufacturing technologies, we show that two-photon laser lithography allows a highly resolved fabrication of multiple, almost arbitrary standardized calibration geometries on a micron length scale. Hereby, all structures are fabricated on only one single substrate, therefore enabling a mapping of a broad range of metrological characteristics for topography characterization. The most required calibration geometries are manufactured and analyzed regarding their aging behavior, their quality improvement by a post-UV development and the resolution limits within the manufacturing as well as the calibration process. Thus, the general industrial and scientific relevance of manufacturing material measures with two-photon laser lithography is demonstrated.

Diffractive optical elements (DOEs) are widely used in various applications such as material processing, illumination, medical, and sensor applications by providing a shape on demand of laser beams. In contrast to refractive optical elements, the effect of DOEs is based on modulating the phase of the beam locally. This creates an interference pattern of the beam. The more height levels are implemented in a DOE, the higher its diffraction efficiency. Rapid fabrication and testing in practice of new designs is desirable to shorten the prototyping development cycle of DOEs. High Precision 3D Printing via a two-photon absorption (TPA) process initiating a polymerization reaction allows manufacturing of virtually any 3D-shaped object, thus being the technique of choice to fabricate DOEs at high precision with an arbitrary number of levels within short time periods. We demonstrate the use of High Precision 3D Printing to fabricate DOEs to be used as beam-shaping and beam-splitting elements, respectively. Different exposure strategies in polymer-like materials are used to fabricate DOEs which have significant impact on the fabrication time. The quality of the fabricated DOEs will be assessed by a variety of characterization methods such as metrology investigations for determination of the surface quality (for example, shape deviations, roughness), AFM, and optical characterization. The impact of different exposure strategies on the final DOEs will be presented and discussed.

Additive manufacturing and 3D printing have seen significant improvements in terms of processing and instrumentation with the aim of increasing the complexity of the objects constructible, increasing resolution and lateral dimensions as well as speed of manufacturing. Interestingly, the choice of materials has not been increasing significantly. One of the oldest materials mankind has used was, until now, missing: Glass. Account of man-made objects in glass date back to 5000 BC which makes it the oldest artificial material used by mankind. Glass has numerous advantageous properties including unmatched optical properties, mechanical, thermal as well as chemical stability to name but a few. However, due to the fact that class can almost exclusively processed by etching using hazardous chemicals or from the melt (i.e., at temperature in the range above 1500 °C) glass has remained, until now, a material inaccessible for modern manufacturing methods including 3D printing. Our group has recently introduced a major paradigm shift in the processing of glass with the introduction of a “Liquid Glass” nanocomposite which can be shaped at room temperature using methods known from polymer replication as well as modern 3D printing techniques. The nanocomposite is a honey-like transparent syrup which can be cured by light and, after thermal debinding and sintering, yields three-dimensional components with transparency, as well as chemical and mechanical properties identical to pure fused silica glass. The surface quality of these components meets the demand of (micro)optics and allows the manufacturing of diffractive and refractive optical elements as well as lenses.

Glass-ceramics play an important role in todays science and industry as it can withstand immense heat, mechanical and other hazards. Consequently, there is a need to find ever-new ways to acquire more sophisticated free-form 3D ceramic and glass structures. Recently, stereo-lithographic 3D printing of hybrid organic-inorganic photopolymer and subsequent pyrolysis was demonstrated to be capable of providing true 3D ceramic and glass structures. However, such approach was limited to (sub-)millimeter scale, while one of the aims in the field is to acquire functional 3D glass-like structures in micro- or even nano-dimensions. In this paper, we explore a possibility to apply ultrafast 3D laser nanolithography in conjunction with pyrolysis to acquire glass-ceramic 3D structures in micro- and nano-scale. Laser fabrication allows production of initial 3D structures with relatively small (hundreds of nm) feature sizes out of hybrid organic-inorganic material SZ2080. Then, a post-fabrication heating at different temperatures up to 1000°C in Ar , air or O₂ atmospheres decomposes organic part of the material leaving only the glass-ceramic component of the hybrid. As we show, this can be done to 3D woodpiles and bulk objects. We uncover that the shrinkage during sintering can reach up to 40%, while the aspect ratio of single features as well as filling ratio of the whole object remains the same. This hints at homogeneous reduction in size that can be easily accounted for and pre-compensated before manufacturing. Additionally, the structures prove to be relatively resilient to focused ion beam (FIB) milling, hinting at increased rigidity. Finally, thermal gravimetric analysis (TGA) and Fourier transform infrared micro-spectroscopy measurements are performed in order to uncover undergoing chemical and physical phenomena during pyrolysis and composition of the remnant material. The proposed post-processing approach offers a straightforward way to downscale true 3D micro-/nanostructures for applications in nanophotonics, microoptics and mechanic devices with improved performance while being highly resilient to harsh surrounding conditions.

This work is dedicated for statistical investigation of laser induced damage threshold of a 3D fs laser lithography produced objects. Arrays of identical polymeric structures are produced out of different materials common in 3D printing and lithography and subjected to varying laser fluence resulting in polymeric objects either being damaged or not. Then, according to the damage probability, linear approximation is used to determine laser induced damage threshold in such structures. This way it is determined, that non photosensitized hybrid organicinorganic zirconium containing SZ2080 is the most resilient material in comparison to photosensitized SZ2080, other hybrid photopolymer OrmoClear, popular in lithography SU8 and Ember Clear used in 3D printing. Acquired results are compared to those obtained by other measurement techniques, advantages and drawbacks of such investigation are discussed.

BSWs are non-radiative electromagnetic waves confined at the interface between a truncated periodic dielectric multilayer and a surrounding media. As an alternative to SPPs (Surface Plasmon Polaritons), BSWs show dramatically enhanced propagation lengths up to several millimeters range and provide new optical opportunities such as the possibility to obtain TE or TM-polarized surface waves. They have found numerous applications in vapor sensing, biosensing, fluorescence detection and imaging, and integrated optics. In this work, we propose a 1DPhC with a thin film of LiNbO3 (TFLN) as the top layer of the multilayer structure. The bonding of LiNbO3 into the 1DPhC structure brings anisotropy and nonlinear properties into the whole crystal allowing the tunability of the BSW devices. Here we present 1DPhCs, which are able to sustain surface waves at the LiNbO3/air interface. Two different geometries have been studied, fabricated and optically characterized. The first one is based on the LiNbO3 membrane suspended in air and the second one is held by a stable glass platform. The multilayer of the membrane based crystal is as following: air/6 pairs of Si3N4(200nm) and SiO2(215nm)/TFLN(1.1μm) – polished from bulk LN/air. The multilayer of the glass supported crystal is as following: glass/UV glue/6 pairs of Si3N4(220 nm) and SiO2(490nm)/TFLN(386nm)/air. 1DPhCs were characterized in Kretschmann configuration at visible and IR wavelengths.

With the purpose of designing a liquid-filled variable focus lens with a large optical aperture and high-speed performance, an investigation research and a series of comparison experiments were conducted. One of the foundings is that the eigenfrequencies of the actuation unit and the lens' dynamic surface profile will become the critical parameters when the lens aperture becomes large. Mechanics analysis of the deformation was studied, and a series of the lens prototype was built.

We investigated the spectral response of complex fiber micro-knots. We found reach spectral response for both transmitted and reflected light from these complex micro-knots. We analyzed these complex micro-knots and found good agreement between the calculated and the measured results.

Optical coherence tomography (OCT) is increasingly used in areas such as ophthalmology and contact lens metrology. However, in such cases, image distortion can occur due to the non-planar nature of the measured sample. Postprocessing algorithms can be implemented to correct this distortion. Here we present an OCT phantom designed to confirm the validity of post-processing algorithms used for measuring curved surfaces. A multi-purpose OCT phantom has been created within a fused silica plano-convex lens using the direct femtosecond laser writing technique. This phantom can be used to calibrate and quantitatively assess the performance (e.g. resolution, sensitivity and distortion) of OCT systems and associated post-processing algorithms for curved structures such as lenses. This novel OCT phantom has been characterized using an optical microscope and OCT systems.

In this work the principles of fabrication of 3D scaffolds via stereolithography and scaffolds’ biocompatibility are investigated. Cells can be seeded into 3D printer-formed structures and artificial tissue or organ can be grown and implanted into human body. In this work the requirements of reproducing the original environment of cells in such bioscaffolds are used in order to create and test mechanically flexible microporous structures. New materials and suitable scaffolds’ geometries might bring desired features in tissue engineering. The scaffolds were fabricated using the tabletop 3D printer Autodesk Ember. Commercial photoresin Formlabs Flexible was used for this task. Optimization steps presented in this paper allowed to increase the biocompabaility of the scaffolds by 48% in comparison to unoptimized ones.

Liquid lenticular lens array can solve the disadvantages of currently available lenticular type three-dimensional (3D) display with solid lenses in that it enables 2D-3D conversion and has no complex calculations to fabricate. Liquid lenticular lens array needs a chamber which contains liquids and this chamber is usually made of a polymer-based plastic such as poly methyl methacrylate (PMMA) and poly carbonate (PC). However, oil acting as a lens permeates into these plastics because they are porous. For this reason, although the liquid lenticular lens array has many advantages, it is not easy to apply to 3D display system because of its short life time. In this paper, the liquid lenticular lens array with a new chamber using Pyrex glass is presented. A multilayer of metal, Cr/Au/Cr/Au, in combination with AZ2070 photoresist was used for wet etching of glass which was conducted in concentrated hydrofluoric acid (HF). The metal multilayer was deposited by using the thermal evaporator and serves as a mask for glass etching and another Cr/Au/Cr/Au multilayer was deposited on the opposite part of the glass. The Pyrex glass was etched at a rate of 7.5μm/s in 49% HF solution. With the completed Pyrex chamber, the liquid lenticular lens array was fabricated and operation tests were done. We also compared the new liquid lenticular lens array with the Pyrex glass chamber to one with the polymer-based plastic chamber in regard to reliability.

There are various methods of patterning electrodes in a MEMS process. However, it is difficult to pattern electrodes in a 3-dimensional structure. One way to overcome these drawbacks is to use a shadow mask. This approach allows electrodes to be deposited on selected areas even if the substrate is not flat. In this paper, a SU-8 shadow mask that is inexpensive and easy to fabricate is proposed. Another advantage of the SU-8 shadow mask is reusability. Most importantly, it is possible to deposit a microscale electrode on 3-dimensional structure with the SU-8 shadow mask. Here, the electrode was deposited on the chamber of an electro-wetting lenticular lens. The chamber structure of the electrowetting lenticular lens has a long reversed trapezoidal shape. In order to adjust the optical axis in the electro-wetting lenticular lens, electrodes should be deposited on each sidewall of the chamber. It was verified that the electrodes were successfully separated with use of the SU-8 shadow mask and the width of the electrode was 50μm.