Dwell time assisted grinding. - In: 2nd EOS Conference on Manufacturing of Optical Components 2011, ISBN 978-1-61839-607-5, (2012), S. 49-50
Optical freeform surfaces in integrated optical microsystems. - In: Imaging systems and applications, (2012), insges. 3 S.
Freeform surface provide degrees of freedom which are essential specifically for the optimization and integration of optical microsystems. We discuss design, optimization as well as fabrication concepts and applications of (micro-)systems involving such non-conventional surfaces.
http://dx.doi.org/10.1364/ISA.2012.IM3C.3
Chromatic information coding in optical systems for hyperspectral imaging and chromatic confocal sensing. - In: Optical systems design 2012, 2012, 85500D, insges. 10 S.
Planar plano-convex microlens in silica using ICP-CVD and DRIE. - In: Optical systems design 2012, 2012, 85500T, insges. 7 S.
A microlens suitable for integration with photonic elements on the same substrate is presented. It is fabricated utilizing planar standard technologies such as UV lithography, ICO-CVD and Deep Reactive Ion Etching. For reaching an optical 3D functionality with 2D structuring methods a variation of the refractive index during the layer desposition process in the vertical direction is used. For the horizontal direction, parallel to the substrate, the shape of etched side walls determines the focus. This procedure allows the independent control of light propagation in two perpendicular directions with planar technologies. To demonstrate the potential of the technology, optical elements for the collimation of fiber-beased light sources are presented.
Simultaneous trapping and observation optics for micro-opto-fluidic systems. - In: EOS annual meeting 2012 (EOSAM 2012), ISBN 978-3-9815022-4-4, (2012), insges. 2 S.
The two step phase-shifting interferometry is a challenging technique for many on-axis holographic applications. The significant advantage is the high dynamic and lateral resolution. Practically it is possible to reconstruct the initial complex wave signal with the resolution of the matrix detector (pixel wise). In this contribution we assume an analytical generalization of the two-step-phase-shifting algorithm. The suggested method is similar to the solution of Meng et al. (Opt. Lett. 31(10), 1414-1416, (2006)) but operates with two reference waves arbitrary in phase and amplitude. Because of the complexity of the analytical expressions a graphical method for solving the duality problem is proposed. The simulation of the reconstruction process shows the reliability of the method.
Adaptive confocal approach to hyperspectral imaging. - In: EOS annual meeting 2012 (EOSAM 2012), ISBN 978-3-9815022-4-4, (2012), insges. 2 S.
We discuss new concepts for hyperspectral imaging based on adaptive chromatic confocal sensors. Design, fabrication and characterization of a sensor system utilizing diffractive and/or refractive Alvarez phase plates are presented.
Micro-nano integration of a III-N nanowire based opto-chemical detector. - In: EOS annual meeting 2012 (EOSAM 2012), ISBN 978-3-9815022-4-4, (2012), insges. 2 S.
Due to the highly sensitive photoluminescence (PL) response to hydrogen (H2) and oxygen (O2), III-N nanowire heterostructures (NWHs) can be applied as opto-chemical transducers [1]. In our contribution we describe the optical design and the fabrication of a robust and compact micro optical system realizing the integration of electro-optical components and NWHs. The potential of our approach is evaluated by profilometric characterizations and an investigation of the optical performance. Furthermore, we discuss the application as highly sensitive sensor system with fully integrated all optical readout for H2- or O2-concentrations in the ppm regime.
Imaging gratings with modulated blaze - realized by a combination of holography and reactive ion beam etching. - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 113.2012, A3, insges. 2 S.
http://www.db-thueringen.de/servlets/DocumentServlet?id=21435
Laser power stabilization for improved ablation depth uniformity . - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 113.2012, B22, insges. 2 S.
Due to low heat deposition into the surrounding material, ps-lasers are well suited for a precise ablation of micro structures. However, to obtain constant removal rates the laser parameters as well as the environmental conditions need to be kept stable. For our investigations we used a frequency tripled ps-laser operating at 355 nm. Without any additional power stabilization system, long term micro structuring processes of OFE-copper typically resulted in depth variations of about +/- 10 % which are strongly correlated with detected laser power fluctuations. The developed system for laser power stabilization takes advantage of the linear polarized radiation of our laser source. With a fast photoelectric detector the power fluctuations are measured. A specifically designed feedback control system turns a half wave plate mounted in a piezo driven rotation stage to decouple fluctuating power fractions via a polarizing beam splitter. We demonstrate a nearly constant laser power at the work piece. Substantially improved ablation depth uniformity is verified by a profilometric analysis of directly ablated diffractive structures.
http://www.db-thueringen.de/servlets/DocumentServlet?id=21324
Novel vision aids for people suffering from Age-Related Macular Degeneration. - In: DGaO-Proceedings, ISSN 1614-8436, Bd. 113.2012, B28, insges. 2 S.
In Germany alone, about 4.5 million people suffer from Age-Related Macular Degeneration (AMD), a disease that causes progressive damage to the central part of the retina. People suffering from AMD usually experience growing dark or blurred spots in the center of their vision which render them unable to read texts, to drive cars, or to recognise faces. Current vision aids for AMD patients are mainly based on the magnification and/or the redirection of the full field of view which will inevitably result in a loss of information at the outer parts of the field of view. In contrast, we present different optical principles for the redirection of the central part of the field while the loss of information at the boarders is kept to a minimum. Our focus is on highly integrated, nonelectric, spectacle-like systems. Possible principles include the field dependent displacement and magnification/reduction of the object information as well as a deliberately induced distortion. Our contribution includes the mathematical and optical modelling of the imaging setup, numerical simulations as well as the presentation of first experimental results.
http://www.db-thueringen.de/servlets/DocumentServlet?id=21325