Application of an interferometric phase contrast method to fabricate arbitrary diffractive optical elements. - In: Applied optics, ISSN 2155-3165, Bd. 47 (2008), 14, S. 2550-2556
A novel approach for the fabrication of diffractive optical elements is described. This approach is based on an interferometric phase contrast method that transforms a complex object wavefront into an intensity pattern. The resulting intensity pattern is used to expose a photoresist layer on a substrate. After development, a diffractive phase object with an on-axis diffraction pattern is achieved. We show that the interferometric phase contrast method allows a precise control of the resulting intensity pattern. An array of blazed Fresnel lenses is realized in photoresist by using kinoform or detour-phase computer holograms for the interferometric phase contrast setup.
https://doi.org/10.1364/AO.47.002550
Diffractive and defractive micro-optics. - In: Optical systems, industrial applications, emerging topics, [index], (2008), S. 65-99
Beam homogenizers based on chirped microlens arrays. - In: Optics express, ISSN 1094-4087, Bd. 15 (2007), 10, S. 6218-6231
http://dx.doi.org/10.1364/OE.15.006218
Tuneable planar integrated optical systems. - In: Optics express, ISSN 1094-4087, Bd. 15 (2007), 17, S. 10607-10614
Planar integrated free-space optical systems are well suited for a variety of applications, such as optical interconnects and security devices. Here, we demonstrate dynamic functionality of such microoptical systems by the integration of adaptive liquid-crystal-devices.
http://dx.doi.org/10.1364/OE.15.010607
Modified phase contrast for recording of holographic optical elements. - In: Optics letters, ISSN 1539-4794, Bd. 32 (2007), 14, S. 2067-2069
A modified phase contrast method is described for the fabrication of holographic optical elements with in-line diffraction patterns. In this method, a liquid crystal phase modulator is addressed by computer-generated holograms to achieve variable phase gratings. The phase gratings are imaged onto photosensitive material by a phase contrast method without a Fourier filter. We show the analytical treatment of the modified phase contrast method and demonstrate the application in holographic recording.
http://dx.doi.org/10.1364/OL.32.002067
Rigorous analysis of shadowing effects in blazed transmission gratings. - In: Optics letters, ISSN 1539-4794, Bd. 31 (2006), 24, S. 3638-3640
Blazed transmission gratings have become crucial components in many hybrid optical systems. Shadowing effects are known to occur at their passive blaze facets, which may impair the systemâs efficiency performance. - For optical designs, it is desirable to have a simple but accurate description of this phenomenon. We show that the efficiency reduction in low diffraction orders is dominated by a linear dependence on the ratio of wavelength to grating period rather than a quadratic dependence as proposed in extended scalar theory. - The strength of the electromagnetic shadowing will be determined using rigorous diffraction methods and discussed with respect to imaging optical components. Results are compared to existing ray-optical models.
http://dx.doi.org/10.1364/OL.31.003638
Integrated free-space optical interconnect fabricated in planar optics using chirped microlens arrays. - In: Optics express, ISSN 1094-4087, Bd. 14 (2006), 22, S. 10765-10778
We present a compact design for an integrated interconnect based on a hybrid imaging setup combining microchannel and conventional imaging. Within this setup the conventional imaging is performed by an aluminum-coated spherical lens. The aberrations introduced by this spherical mirror to the channels of the interconnect can be compensated by channel-wise adapted microlenses located at the in- and output interfaces. These microlenses are used for collimating or refocusing the beams, respectively. Within this paper we present the design of the microlens array with individually shaped lenses referred to as chirped mircolens array (cMLA) based on numerical optimization and the use of fitting functions. Further on we focus on the fabrication of the chirped microlens arrays by laser lithography and first experimental results of coupling efficiencies of singlemode as well as multimode fibers for the realized prototypes.
https://doi.org/10.1364/OE.14.010765
Design considerations for efficient planar-optical systems. - In: Optics communications, ISSN 1873-0310, Bd. 267 (2006), 1, S. 74-78
Planar integrated free-space optics is well suited for various applications, e.g., in telecommunication, optical interconnects and security application. However the overall efficiency of purely diffractive systems is low, i.e., in the range of a few percent. We show that it is possible to raise the efficiency significantly by integration of refractive optical elements (prisms, wedges) for coupling into the substrate. - In this case, the systems design is particularly challenging. We compare the impact of different coupling mechanisms on the optical designs of integrated 4f-imaging systems.
http://dx.doi.org/10.1016/j.optcom.2006.06.041
Zur Abbildung lichttechnischer Größen. - In: Jahrbuch Optik und Feinmechanik, ISSN 0075-272X, Bd. 52 (2006), S. 121-132
Planar microoptical systems for correlation and security applications. - In: Optical imaging sensors and systems for homeland security applications, ISBN 978-0-387-26170-6, (2006), S. 339-366
Optical and photonic systems and devices have significant potential for homeland security. "Optical Imaging Sensors and Systems for Homeland Security Applications" presents original and significant technical contributions from leaders of industry, government, and academia in the field of optical and photonic sensors, systems and devices for detection, identification, prevention, sensing, security, verification and anti-counterfeiting. The chapters have recent and technically significant results, ample illustrations, figures, and key references. This book is intended for engineers and scientists in the relevant fields, graduate students, industry managers, university professors, government managers, and policy makers.