This PDF file contains the front matter associated with SPIE Proceedings Volume 10930, including the Title Page, Copyright information, Table of Contents, Author and Conference Committee lists.

Nanoscale optoelectronic devices based on coplanar nanogap electrodes, when compared with traditional vertical devices, exhibit attractive characteristics, such as high density of integration, high sensitivity, fast response and multifunctionality. Moreover, their low-cost high-throughput fabrication on flexible disposable substrates opens up several new applications in sectors ranging from telecommunications and consumer electronics to healthcare - to name a few. However, their commercial exploitation has been hitherto impeded by technological bottlenecks, owing to the incompatibility of currently available fabrication techniques, eg. e-beam lithography, with industrial upscaling. Adhesion lithography is a nanopatterning technique that allows the facile high yield fabrication of coplanar metal electrodes separated by a sub-15 nm gap on large area substrates of any type, including plastic. These electrodes, when combined with solution-processed and/or low-dimensional nanostructured materials deposited at low, plastic-compatible, temperatures give rise to nanoscale optoelectronic devices with intriguing properties. It will be shown that both nanoscale light-emitting and light-sensing devices can be fabricated upon using light-emitting polymers along with self-assembling surface modifiers, and lead halide perovskites and functionalised colloidal PbS quantum dots, respectively. Emphasis will be given in recent advances in flexible nanoscale photodetectors fabricated with nanogap coplanar electrodes, operating in DUV up to NIR part of the spectrum. These devices exhibit high responsivity, sensitivity and fast response speed (hundreds of nanoseconds) owing to the extreme downscaling of key device dimensions. These results demonstrate that adhesion lithography combined with advanced materials concepts constitutes a new fabrication paradigm enabling a plethora of advanced applications within the field of flexible electronics.

Membrane projection lithography (MPL) is a fabrication approach in which a novel process flow and mature silicon processing equipment combine to create three-dimensional metamaterials with size scales operational at optical frequencies. In its most common realization, MPL leverages microelectromechanical (MEMS) processing techniques to create cubic unit cells with silicon walls, planarized by chemical mechanical polishing (CMP), a technique that is not omnipresent in fabrication facilities. Here we show several variants of MPL, two of which do not require CMP to make the MPL process compatible with low-tech fabrication environments and open the MPL process to a wider audience.

Here we report a novel fabrication approach which enables to integrate 2D nanostructures on the facet of optical fibers by electron beam lithography. The general idea behind this fabrication approach is to planarize the fiber surface in order to fit planar fabrication technology, i.e., that the fibers can be treated in the same way as typical wafers. To demonstrate our approach, we have implemented two types of gold structures on the on the end face of 50 cm long standard single mode fibers (SMF-28): the one is gold nanotrimers lattice and the other is nanodots array. The former is employed as a novel refractive index sensor with a sensitivity of 390 nm/RIU, which represents the state-of-the-art for such a device type. The latter significantly improves the fiber light-collecting ability at an oblique incidence angle with a maximum acceptance angle of 80° breaking the limitation of conventional fiber. This fabrication method is not limited to the nanostructure geometry reported here and can also be applied to dielectric nanostructures, thus opening up the field of fiber optics for planar nanostructures within numerous application fields including bioanalytics, telecommunications, nonlinear photonics, optical trapping and beam shaping.

Two-photon lithography based 3D Direct Laser Writing (DLW) has shown its unique potential as a method to fabricate and integrate miniaturized optical elements which can parallel the function of bulk optical elements used in large scale systems [1]. Up to now, this fabrication method has been mainly used to obtain reflective, refractive and diffractive optical elements. The difficulty on using and controlling printable materials with intrinsic birefringence in 3D DLW has so far prevented the scaling down of polarization retarders elements. Here we present the DLW fabrication of a miniaturized Fresnel Rhomb, which is a prism in which the light gets reflected two times with a precise incidence angle to have a 90 degrees phase shift between the p and s polarization components, thus acting as a quarter-waveplate. Being not based on an intrinsically birefringent material, this optical element features a very broadband behavior covering a band exceeding 300 nm. To demonstrate the direct integration and flexibility provided by this method we have printed a miniaturized optical assembly consisting of the Fresnel Rhomb and a collimating micro lens on a polarization maintaining optical fiber so as to obtain a miniaturized on-fiber broadband source of pure circularly polarized light. This structure could find application to create a remote ultra compact probe in circular dichroism and Raman Optical Activity spectroscopies but could also be used as a phase retarder for other integrated applications, where control of the polarization on small scales is needed. [1] Dietrich, P. I., Blaicher, M., Reuter, I., Billah, M., Hoose, T., Hofmann, A., et al. (2018). In situ 3D nanoprinting of free-form coupling elements for hybrid photonic integration. Nature Photonics, 1–9. http://doi.org/10.1038/s41566-018-0133-4

Applying a technique inspired by super-resolution imaging, it is possible to achieve sub-diffraction limited linewidths in far-field photolithography. Using interference lithography as a demonstration platform, and exposing with a wavelength of 364 nm, we demonstrate high fidelity 50 nm features. Furthermore, these features are written over a large area with high uniformity and repeatability. As only off-the-shelf photoresists are used, this method is compatible with existing cleanrooms and adaptable to some existing lithography tool sets. We develop a model to analyze the lithographic process. From this model we show that there are fundamental limits imposed by both the optics and the photoresist. Also from the model, we demonstrate how to deterministically control sub-diffraction linewidths. Next, we analyze the design of an interference lithography tool. As sub-diffraction performance is in part limited by the aerial image quality, we consider the effects of component selection and alignment on final lithographic patterns. Additionally, we analyze the lithographic errors introduced, for example by wavefront distortion. Experimental verification is given for the analysis. Unique to this demonstration, a refractive beam shaper is employed to allow uniform exposure over a large area without sacrificing power. To our knowledge this is one of the first experimental demonstrations of a beam shaper in interferometric lithography.

Micro-lens array manufacturing by using an inkjet printing technology allows for the manufacturing of large area arrays on lithographically structured substrates that contain oleophobic and oleophilic surface patterns. An inkjet printing process deposits the high performance, hybrid polymer ORMOCER on the oleophilic pattern. The material forms by means of surface tension and wetting boundaries a lens shape, while the inkjet printing process itself enables for a highly parallel manufacturing of many lenses at the same time. A typical geometrical deviation <2% of the radius of curvature for lenses with diameters of <1 mm, ROC’s of ca. <2 mm and sag heights of <100 microns was achieved. Also a specific lithography processing regime was derived that combines wetting patterns with optical apertures to enable advanced illumination setups like multi-aperture projection.

Atomic force microscope (AFM) probes are the product of exceptionally refined silicon micromachining, but these structures, and AFM imaging by extension, are restricted by the limitations of these fabrication techniques. Here, the nanoscale additive manufacturing technique direct laser writing (DLW) is explored as a method to print monolithic cantilevered probes for AFM. Not only are these 3D printed probes found to function effectively for AFM, but they also confer several advantages, most notably the ability to image in intermittent contact mode with a bandwidth approximately ten times larger than analogous silicon probes. In addition, the arbitrary structural control afforded by 3D printing was found to enable programming the modal structure of the probe. These capabilities could be useful in the context of resonantly amplifying non-linear tip-sample interactions. Additionally, we explore two new architectures of 3D printed AFM probes that allow these structures to impact the fields of multi-probe imaging and lithography. Collectively, these results show that 3D printed probes complement those produced using conventional silicon micromachining and open the door to new imaging techniques.

Waveguide-coupled sensors have several applications such as magnetometry, electrometry or thermometry, harnessing the resolution of nano-sized probes as well as tight light control in macroscopic waveguide networks. We present our approach to incorporate nanodiamonds into direct-laser-written (DLW) three-dimensional photonic structures. The nanodiamonds house ensembles of 10^3 nitrogen vacancy (NV) centers, acting as probes that can be read-out optically. Guided by the waveguide structure, detection of the optical signal from the nanodiamond does not require direct optical access. In fact, our waveguides combine extended planar sections laid onto the substrate on the one hand with three-dimensional coupling structures on the other hand. The latter effectively rotates the propagation direction of light signals from parallel to the substracte surface within the waveguide network to perpendicular to the substrate at the in- and outputs. This enables simultaneous addressing and imaging of waveguide inputs and outputs through the glass substrate using a single microscope objective. The NV center offers an accurately controllable spin in a solid-state system, serving as a sensitive probe of, e.g., magnetic fields. Additionally these defect centers are photostable and compatible with the DLW process. We show optically detected magnetic resonance spectra together with Rabi oscillations on an effective two-level system in waveguide-embedded nanodiamonds. We compare their performance with free-space emission and complement our experimental studies by numerical simulations. This approach opens the way for on-chip three-dimensional structures for optically integrated spin-based sensing.

We report on the imaging of latent 3D features exposed in photoresist during Direct Laser Write micro-/nanofabrication. The imaging method is based on monitoring of photoluminescence emitted by photonitiator in the photoresist, and exploits photoluminescence quenching and its dependence on the dose of the previous optical exposure. By spatially scanning focus of a low-intensity laser beam over the previously recorded latent features, spatial PL intensity maps reveal negative image of the latent pattern, and allows determination of feature size and shape prior to development. The imaging can be carried in situ, immediately after the fabrication, and does not require extensive modification to the existing equipment.

Fabrication of 3D dielectric photonic crystals in the visible and in the infrared range typically requires sub-micron structural features and high-refractive index materials. We developed a template-free additive manufacturing (AM) process based on direct laser writing (DLW) that can create complex 3D architectures out of titania (TiO₂) with ~100 nm resolution. In this process, we synthesize hybrid organic-inorganic materials that contain titanium clusters coordinated with acrylic ligands to prepare a photoresist that is amenable to two-photon lithography (TPL). We sculpt a pre-ceramic architecture using TPL and then pyrolyze in air at 900°C to remove the organic constituents to produce a replica of the original structure with ~70% reduced linear dimensions. Energy-Dispersive Spectroscopy (EDS) and Raman spectroscopy confirm the constituent solid to consist predominantly out of rutile titania.

We demonstrate this process by fabricating titania woodpile structures with lateral dimensions of 70 × 70 μm and lateral periodicities between 1.0 and 1.3 μm. Fourier Transform Infrared (FTIR) spectroscopy reveals passive tuning of the reflectance peak between 1.7 and 2.3 μm, which agrees with Plane Wave Expansion simulations. This titania AM process offers a promising pathway to efficiently fabricate complex 3D nano-architectures out of a high-index material for 3D dielectric photonic crystals in the visible and the infrared.

Precise determination of the position of a single point source (e.g. fluorescent molecule/protein, quantum dot) is at the heart of microscopy methods such as single particle tracking and super-resolution localization microscopy ((F)PALM, STORM). Localizing a point source in all three dimensions, i.e. including depth, poses a significant challenge; the depth of field of a standard high-NA microscope is fundamentally limited, and its point-spread-function (PSF), namely, the shape that a point source creates in the image plane, contains little information about the emitter’s depth. Various techniques exist that enable 3D localization, prominent among them being PSF engineering, in which the PSF of a microscope is modified to encode the depth of the source. This is achieved by shaping the wavefront of the light emitted from the sample, using a phase mask in the pupil (Fourier) plane of the microscope. In this talk I will describe the use of PSF engineering for encoding the depth and color of a sub-diffraction fluorescent emitter. I will present experimental results of tracking and imaging synthetic fluorescent sources and bio-molecules, and discuss the unique fabrication considerations and challenges associated with these applications. Different methods of phase modulation will be considered and evaluated.

The positioning range of ultra precise positioning systems is restricted to certain hundreds of micrometers in lateral direction due to the application of piezoelectrical stages. Using galvanometer scanner, the range is limited even to tens of micrometer or by restriction of accuracy. Direct laser writing processes can be done with a combination of both positioning techniques, but structures in the millimeter range can only be achieved by using stiching methods. The nanopositioning and nanomeasuring machine NMM-1, developed at TU Ilmenau together with SIOS Meβtechnik GmbH, provides a large positioning volume of 25 mm × 25 mm × 5 mm with a positioning resolution in the sub-nanometer range. A combination of this precise positioning machine with common laser writing tools like UV direct laser writing or two-photon polymerization enables to produce structures with metrological traceability. The laser writing techniques base on both one-photon absorption and two-photon processes in the used photosensitive materials. Therefore, a 405 nm fiber-coupled laser diode for the one-photon processes and a 805 nm femtosecond laser are guided through an objective onto the positioning stage of the NMM-1. In first experiments, structures with sub-10 μm linewidths could be achieved. Furthermore, a probe system consisting of a hologram laser unit with a wavelength of a 650 nm is applied to the setup to control the focus spot of the machining laser onto the sample’s surface. That leads to a further decrease in the linewidths of the structures.

Photonic analogs of topological insulators conduct light along their edges scattering-free. Moreover, the flow along the edges is unidirectional, prescribed by the topological invariant, an attribute of the bulk of the system. As long as the topological properties persist, the edge transport is not even perturbed by defects. This connection is enforced by the bulk-boundary correspondence. However, this correspondence principle is modified under time-periodic driving. In our work we show that for certain defects the protection of an edge state is destroyed, although the topological properties of the bulk are unchanged. Theoretical predictions are verified by experiments in a photonic model systems of 3D printed evanescently coupled dielectric waveguides[1,2]. In particular, we consider a dimer chain (SSH) with a defect in the center of the chain, breaking the dimerization and inducing an edge state [3]. This edge state is protected, as it lies in a bandgap. We drive the defect by periodically modulating its position in the y- direction, leaving the bulk unaltered. The periodic modulation results in Floquet copies [4,5] of the edge state with higher energy, spaced by the driving frequency around zero energy. Whenever the driving frequency is such that the replicas overlap with the bulk bands the edge state couples to the bulk states, i.e. the light does not remain localized at the defect site. Although the bulk of the system, and as such the topological invariant, remains unchanged, topological protection breaks down for certain driving frequencies. References [1] C. Jörg et al., New J. Phys. 19, 083003 (2017). [2] Z. Cherpakova, C. Jörg et al., arXiv:1807.02321 (2018). [3] A. Blanco-Redondo et al., Phys. Rev. Lett. 116, 163901 (2016). [4] M. Holthaus, J. Phys. B: At. Mol. Opt. Phys 49, 013001 (2016). [5] S. A. Reyes et al., New J. Phys. 19, 043029 (2017).

We demonstrate the experimental realization of a uniform synthetic magnetic flux and the observation of Aharonov-Bohm cages in ultrafast-laser-fabricated photonic rhombic lattices. We engineer modulation-assisted tunneling processes that effectively produce complex-valued tunneling matrix elements leading to a non-zero magnetic flux per plaquette. In other words, the synthetic magnetic flux is generated by applying a strong linear detuning of the propagation constants along the lattice – in order to suppress the effective inter-site tunneling – and then by resonantly modulating the propagation constants with a required phase of modulation to restore and control the effective tunneling amplitudes. This synthetic magnetic field for light can be tuned by varying the phase of the modulation. When half a flux quantum is realized in each plaquette, all the energy bands collapse into non-dispersive (flat) bands and all eigenstates are completely localized in real space [1,2]. We demonstrate this magnetic flux induced localization phenomena, known as Aharonov-Bohm caging, by launching input states that overlap with the flat-band states and observing breathing motions of the optical intensity whose frequency is determined by the energy gaps in the spectrum [3]. Additionally, we explore the dynamics on the edge of the lattice and show how the corresponding edge-states can be continuously connected to the topological edge-states of a Creutz ladder. Our photonic lattice constitutes an appealing platform where the interplay between engineered gauge fields, frustration, localization and topological properties can be finely studied. References: 1. Physical Review Letters 81, 5888 (1998) 2. Optics Letters 39, 5892 (2014) 3. arXiv:1805.03564

A finite SSH-chain has two topologically protected edge states for topologically non-trivial dimerization. By adiabatically changing the coupling strength and the on-site-potentials, these edge states can be transformed into each other (Thouless pump). In between each pump cycle the edge states become delocalized. At this point of the adiabatic transformation, small perturbations, e.g. a hole at one site, do not affect the edge-state exchange much. We investigate how a commutation of neighboring sites will affect the state-exchange. Simulations and calculations show that only one of the edge states is affected by the perturbation. For an experiment it is necessary to be able to create a finite system where it is possible to act specifically on only a few sites to exchange their positions. We suggest using evanescently coupled waveguides. The light intensity along the propagation direction of these waveguides corresponds to the time evolution of a 2D quantum mechanical wave function. To fabricate these waveguides we produce the inverse waveguide structure made of polymer by 3D-micro-printing (direct laser writing). After development we infiltrate the inverse structure with a material with higher refractive index [1]. The on-site potential can be controlled via the radius of the waveguides and the coupling strength via the distance between them. The 3D-trajectories of the waveguides allow realizing a site-exchange by twisting a pair of strongly coupled waveguides around. Long propagation distance relative to the hopping distance is needed to ensure the transformation is adiabatic. [1] Jörg, et al., New J. Phys. 19, 083003 (2017).

Periodic arrays of evanescently coupled optical waveguides – known as photonic lattices – are a powerful experimental platform for exploring a range of semi-classical and quantum phenomena including topological phases of matter. In these artificial crystals of optical waveguides, the dynamics of a single-particle wavefunction can be experimentally emulated by probing the evolution of optical fields along the propagation distance [1]. In many photonic lattice simulators, unlike fiber networks, the effective time-evolution of a specific input state is measured over relatively short timescales, which is set by the maximum propagation distance of the fabricated lattice, and hence, accessing long “time” dynamics constitutes a severe experimental challenge. In this work, we overcome this limitation by placing the photonic lattice inside a (linear or ring) cavity, which allows the optical state to evolve through the lattice multiple times. The accompanying detection method, which exploits a multi-pixel single-photon avalanche detector array [2], offers quasi-real time-resolved measurements after each round trip. We apply the state-recycling and time-resolved detection techniques to ultrafast-laser-fabricated photonic lattices emulating Dirac fermions and anomalous Floquet topological phases [3]. We also show how this new platform allows realizing synthetic pulsed electric fields, which can be used to drive transport within photonic lattices. This work opens a new route towards the long-time-detection of the analogous wavefunction in engineered photonic lattices and the realization of hybrid analog-digital simulators. References: 1. Nature 424, 817 (2003) 2. Custom Integrated Circuits Conference, CICC’09. IEEE, 77–80 (2009) 3. arXiv:1712.08145

Iridescence has long been considered as an intrinsic special feature in structural colors. But we have also learned that iridescence in structural colors can be reduced by incorporating certain degrees of randomness, as demonstrated by the photonic glass and polycrystals. By studying structural colors in two different groups of spiders – the large, non-iridescent blue tarantulas and the tiny iridescent peacock spiders – we have found examples shown iridescence in structural colors can be both reduced and enhanced through the interaction of sub-micrometer photonic structural features, micrometer-scale geometries, and hierarchies without the needs of randomization. To fully understand how iridescence is affected by structures of specialized hairs and scales in these spiders, we use an interdisciplinary biomimetic approach and apply a myriad of characterization, simulation, and prototyping techniques during our investigations, including but not limited to, spectrophotometry, electron microscopy, imaging scatterometry, hyperspectral imaging, finite element analysis, and two-photon nanolithography. We find that blue structurally colored hair from some tarantulas shows multilayer structures with hierarchical cylindrical groove-like configurations along their length, and determine that this hierarchical geometry with its high degree of rotational symmetry (flower-like shape) almost entirely eliminates the iridescence produced by the multilayer structure, producing highly consistent blue color from all viewing angles. On the other hand, the rainbow iridescent scales from some peacock spiders combine nanoscale 2D diffraction grating structures with microscale 3D convex curvature, enabling the scales to separate different wavelengths of light at a higher resolving power than the conventional, flat diffraction grating.

Femtosecond laser based 3D nanolithography is gaining popularity in huge variety of fields. However, further improvements are needed to push it from laboratory level use into a wide spread adaptation. In this work we present several advances needed to achieve this goal. First, linear stage and galvo-scanners synchronization is employed to produce stitch-free mm-sized structures with features down to micrometers. Furthermore, it is shown that by varying objective numerical apertures (NA) from 0.8 NA to 1.4 NA voxel size can be tuned in the range of 330 nm to 1.7 μm in transverse and 1.9 μm to 7.9 μm in longitudinal directions, resulting in voxel volumes from 0.017 μm³ to 3.759 μm³ with structuring rates at 2426 μm³/s and 104767 μm³/s respectively at 1 cm/s translation velocity. This two orders of magnitude tunability is exploited to fabricate various functional structures. It includes 2 mm diameter functional micro-lens, cantilever capable of sustaining multiple deformation cycles and free-movable micromechanical spider and squid (overall size - up to 5 mm), showing possibility to print true 3D hinge-like microstructures (feature size down to micrometers) for possible uses in microrobotics. Overall, the presented results show simple and straight-forward way to combine resolution on-demand and stitch-free 3D laser lithography for functional structure fabrication needed for fast expanding science and/or engineering fields.

The performance of microlenses fabricated via femtosecond direct laser writing is insuperably limited with regards to image contrast within its all-transparent material system. Our proposed super-fine inkjet process for the realization of apertures and non-transparent hulls both shields stray light and adds additional optical design parameters, namely diameter, shape, and position of the aperture. A micropinhole camera, a high-contrast imaging microlens, and a telecentric system are demonstrated. Our method is most suitable for 3D-printed micro-optics due to its one-step integration and auto-adjustment of the aperture position and can be useful for highly precise integration of functional materials beyond mere non-transparency.

Additive manufacturing of optical elements out of polymer allow new design concepts for optics. The parts are built up layer by layer. Unlike polymer binding with glass particles with its sintering process no secondary step is necessary for polymer printing to create the final part. With more and more printers and transparent materials available, this technology becomes more and more relevant for prototyping or custom optics. Therefor a deep understanding of the optical effects in the part is desirable. Key property of optical elements is the refractive index. The materials for polymer printing are most commonly resins that cure under UV-exposure and show lower refractive indices in liquid phase than cured. Assuming a dependency of the refractive index on the grade of polymerization and therefor the UV-exposure, the layering process of additive manufacturing causes variations of the refractive index within the part. Using the Scanning Focused Refractive Index Microscopy, the distribution of the refractive index within and between the layers is analyzed. The analysis includes comparisons between raw parts after printing and parts after UV post curing. Additionally, layer free samples from a Continuous Liquid Interface Printing System are examined for the homogeneity of the refractive index distribution. The purpose of the presentation is to give a detailed insight into the optical effects occurring at the layer interfaces of elements created by additive manufacturing. Possible use cases of the refractive index distributions within the part are also discussed.

This paper presents a holographic fabrication of a new type of photonic crystal, called graded photonic super-crystals with graded basis, dual period and dual symmetry. Pixel-by-pixel phase coding of laser beams in a spatial light modulator can produce the highest resolution in produced photonic super-lattice. Two-level designs in phase pattern are used to generate graded photonic super-crystals where graded square lattice clusters are orientated in four, five or six-fold symmetry. Further phase engineering in a super-cell of 12x8 pixels can produce small-period square lattice orientated in a large period rectangular pattern.

Structural color phenomena exhibited by several organisms result from interference and diffraction of light incident upon multilayer nanostructures. These biomimetic nanostructured surfaces produce structural coloration for desired angle-variant distributions of reflectance spectra. Previous work has demonstrated the utility of inverse design methodologies in the computational formulation of nanostructures tailored for specific spectral responses, generally tailored around a single spectral band. In this work, we depict a design methodology based around computational inverse design for the formulation of nanostructures exhibiting composite structural coloration in a variety of disjoint spectral bands. We furthermore depict example design constraints and study convergence with respect to the design trade space. Such complex biological systems require advanced fabrication techniques, and replication of nanoscale features of this complexity has been difficult. Our designs are constrained for realizable fabrication using direct laser writing techniques such as two-photon polymerization. This process provides a toolkit with which to examine and build other bio-inspired, tunable, and responsive photonic systems and expand the range of achievable structural colors. Sample experimental results of nanostructures fabricated via two-photon polymerization are presented.

Non-uniform surface relief gratings were laser-inscribed on azobenzene molecular glass thin films using a modified Lloyd’s mirror interferometer. The azobenzene films were exposed to an adjustable interference pattern obtained from the recombination of collimated and spherically divergent laser beams. The localized pitch, grating vector orientation and depth of several non-uniform gratings, with central pitches ranging from 500 nm to 2000 nm, were measured and characterized experimentally. These gratings exhibited a chirping or pitch variation along the imposed X-axis as well as an angular change in the grating vector orientation along the imposed Y-axis.

In this work we present a comparative study of two processes for the fabrication of an array of microchannels for microfluidics applications, based on integrated-circuit technology process steps, such as lithography and dry etching. Two different methods were investigated in order to study the resulting microstructures: wet and dry deep etching of silicon substrate. The typical etching depth necessary to the target application is 50 μm.

In view of the increasing demands on precision optics, microelectronics and precision mechanics nanoscale structuring processes are of great interest. It is becoming more and more important to apply a large number of structures that are as small as possible to ever larger areas with high reliability and to increase the number of structures per area element (packing density). The straightness and uniformity of these structures, as well as the positioning accuracy during the fabrication of such narrow lines and points are at the center of the increase of the packing density. A further decisive role is played by the development of suitable sensors and tools for the production and measurement of these structures. The development and the combination of a new laser based probe for the measurement and a direct laser writing (DLW) tool for the creation of sub-micro structures forms the core of this topic. The new sensor is based on a confocal measuring principle. A fiber coupling is used to avoid thermal influences. At the same time, the fiber end itself serves as a confocal pinhole. For the process tool, comprehensive investigations of laser and resist parameters are necessary. The first results are shown. These two parts are investigated separately and combined at the end of the work. In order to achieve the necessary positioning accuracy, the tool is integrated into the Nanopositioning and Measurement Machine (NPMM).

We present a method to write a tapered waveguide using fixed-beam-moving-stage (FBMS) in an electron-beam lithography system. FBMS allows writing of large patterns without stitch-error, however, restricts only a few primitive shapes. For patterning tapers, a combination of FMBS with area-mode is used that typically results in alignment errors. The proposed method offers smooth and alignment-error-free tapering of sub-micron featured Silicon waveguide. We experimentally demonstrate a fully FBMS patterned photonic circuit with power splitter, wire-to-slot coupler, slot waveguide and a slotted ring resonator. The device response with insertion loss -1.35dB is measured using a tunable laser source around 1550 nm wavelength.

In this work we study the evolution of the photonic nanojet (PNJ) phenomenon as the ratio of the sphere’s diameter over the illumination wavelength changes, for microspheres with diameters from 2μm to 100μm. We measure the focal point position by using 3D intensity scanning and identifying the maximum-intensity spot. We also measure the spot size at the focal plane using both intensity and phase data. Finally we use this information to compare the PNJ’s behavior to that of a ball lens and evaluate the importance of chromatic effect in the PNJ phenomenon.