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Wang X.,University of Kassel | Albrecht A.,University of Kassel | Schudy S.,University of Kassel | Woit T.,University of Kassel | And 8 more authors.
INSS 2010 - 7th International Conference on Networked Sensing Systems | Year: 2010

Microspectrometers are very important and reveal a high potential for networked sensing systems. They are widely implemented in both industrial and scientific applications. A novel Fabry-Ṕrot-based nanospectrometer with nanoimprinted cavities has been designed. The key parts of the nanospectrometer are Fabry-Ṕrot filter arrays with different cavity heights which have been fabricated and characterized in detail. All different filter cavities were fabricated in a single step using novel 3D nanoimprint technology with our high vertical resolution 3D nanoimprint templates. Potential combinations of nanoimprint methods and imprint resists were used and characterized. Plasma enhanced chemical vapour deposition (PECVD) and ion beam deposition (IBD) were processed in parallel for depositing distributed bragg reflectors (DBRs). The filter arrays have been demonstrated to have an ultra-high filter transmittance up to 97%, small line width (FWHM) of less than 2.5 nm and a rather broad stop band over 200 nm. © 2010 IEEE.

Mai H.H.,University of Kassel | Albrecht A.,University of Kassel | Woidt C.,University of Kassel | Wang X.,University of Kassel | And 8 more authors.
Applied Physics B: Lasers and Optics | Year: 2012

Fabry-Pérot (FP) filter arrays fabricated by high-resolution three dimensional (3D) NanoImprint technology are presented. A fabrication process to implement 3D templates with very high vertical resolution is developed. Filter arrays with 64 different cavity heights have been fabricated requiring only one single imprint step. Different optical methods are involved in this paper to characterize geometric and spectral properties. In order to investigate the transfer accuracy of the surface quality from the NanoImprint template to the filter, we use white light interferometry (WLI) measurements. Surface roughness and structure height accuracy of <1 nm for both values demonstrate the conservation of these critical parameters during the 3D NanoImprint process. Additionally, an optical characterization methodology for spectral transmission and reflection measurements of the filter arrays is introduced and applied. A compact microscope spectrometer setup which allows efficient handling, high resolution and short inspection time is verified by comparing measurement results to that of an optical bench setup used as a reference. First, this paper focuses on the foundation of the FP filter arrays, second on the technological fabrication, third on validation calibration of the setup and forth on the characterization of the filter arrays. The measurements envisage the spectral position of filter transmission lines, the full width at half maximum (FWHM) and the total spectral bandwidth of the array, i.e. the stopbands of the included Distributed Bragg Reflectors (DBRs). © 2012 Springer-Verlag.

Woidt C.,University of Kassel | Setyawati O.,University of Kassel | Setyawati O.,Opsolution NanoPhotonics GmbH | Albrecht A.,University of Kassel | And 9 more authors.
NATO Science for Peace and Security Series B: Physics and Biophysics | Year: 2011

Producing miniaturized and low-cost components of high precision optical sensors has attracted a wide variety of fields. Fabry-Pérot-based filters can be considerably miniaturized without decreasing high spectral resolution, compared to grating-based spectroscopic devices. The filters are assembled by using MEMS (micro-electro-mechanical-systems) technologies. Tunable Fabry-Pérot filters enable miniaturized sensor components for spectrometers covering a wide area of applications in the visible and near infrared range. We demonstrate a concept of micromachined tunable Fabry-Pérot filters, suitable for precisely selecting very narrow wavelength bands and, thus, by tuning for measuring spectra in the visible and infrared spectral range. These tunable filters integrated into optical devices act as sensors for process monitoring, color detection or medical applications. The design and the fabrication processes are compatible with nanoimprint requirements to assemble arrays of filters for increasing the spectroscopic range. © 2011 Springer Science+Business Media B.V.

Setyawati O.,University of Kassel | Setyawati O.,Opsolution NanoPhotonics GmbH | Engenhorst M.,University of Kassel | Bartels M.,University of Kassel | And 6 more authors.
Journal of Micro/Nanolithography, MEMS, and MOEMS | Year: 2010

We present the characterization of a dry-etching process for high-contrast TiO2/SiO2 distributed Bragg reflectors, by inductively coupled plasma reactive ion etching, focusing on the etch rate and the etch selectivity. Photoresists and metals as etch masks were investigated. An excellent etch profile using an indium tin oxide mask was obtained, with an etch rate of >80 nm/min at a pressure of 6 mTorr. The experiments were developed for structuring Fabry-Pérot filters for tunable optical sensor arrays. © 2010 Society of Photo-Optical Instrumentation Engineers.

Setyawati O.,University of Kassel | Setyawati O.,Opsolution NanoPhotonics GmbH | Engenhorst M.,University of Kassel | Wittzack S.,University of Kassel | And 7 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

We have investigated the etching characteristics of high-index-contrast TiO2/SiO2 DBR mirrors by inductively coupled plasma reactive ion etching (ICP-RIE) with a focus on the etch rate and the etch selectivity by varying etch parameters (gas flow rate, RF and ICP power, pressure and temperature). Chrome, aluminum and ITO (indium tin oxide) were applied as etch masks. Various mixtures of SF6/Ar gas were used for the etch processes. An optimum etch profile was obtained with an etch rate of approximately 80 nm/min at a pressure of 6 mTorr and a temperature of 20°C. The experimental results were applied to develop Fabry-Perot filters for tunable optical sensor arrays. © 2010 Copyright SPIE - The International Society for Optical Engineering.

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