Martin Ebermann

• Doctor of Engineering
• R&D Manager at InfraTec GmbH

This paper reports the development and integration of (Poly‐Si/Air)ⁿ Distributed BRAGG Reflectors (DBR) in a MOEMS Fabry‐Pérot‐Interferometer (FPI) concept. The realized reflectors constitute a promising and resource‐efficient alternative to complex Ion‐Assisted Deposition based DBRs while maintaining their advantages. Compared to state of the art...

A static filter array is developed based on Fabry–Perot cavities operating in the mid‐infrared range from 2 to 4.5 µm, matching the absorption region of several gases relevant for air quality monitoring. The filters include two distributed Bragg reflectors and a high‐index tuning element with varying thickness in between. The filters display high p...

Infrared analyzer with MEMS microspectrometer optimized for handheld explosive gas detection Doris Mutschall1, Martin Ebermann1, Norbert Neumann1, Rainer Krage2, Martin Gorek2 1 InfraTec GmbH, Gostritzer Strasse 61-63, 01217 Dresden, Germany 2 GfG, Gesellschaft für Gerätebau mbH, Klönnestrasse 99, 44143 Dortmund, Germany This paper presents a co...

This report presents recent advances in the design and fabrication of a tunable Fabry-Pérot interferometer (FPI) with subwavelength grating (SWG) reflectors, as well as measurement results and applications. The FPI is designed as wavelength selecting element for highly miniaturized mid-wave infrared spectrometers. The optical resonator of the FPI i...

Many application fields of infrared spectroscopy require small, robust and transportable spectrometers, which are considerable less costly than existing products. Therefore microspectrometer technologies are rapidly emerging and many research groups spend effort on this. Compared to other kinds of devices, micromachined tunable Fabry-Pérot filters...

Microspectrometers based on MEMS Fabry-Pérot interferometers as optical band-pass filters are a recently emerging solution. InfraTec is one of the leading suppliers of tunable infrared MEMS filters for gas analysis. The talk will present a brief overview of the standard MEMS tunable infrared filters and the next generation with enhanced properties.

A tunable MEMS Fabry-Perot infrared filter with subwavelength structured reflectors substituting state of the art Bragg reflectors is presented. The reflectors consist of a disc resonator array arranged on a membrane carrier. The subwavelength structures were simulated and optimized by finite difference time domain analysis in order to achieve high...

This paper presents a toolset for the efficient control of the indoor air quality and thermal comfort in retrofitted buildings. The refurbishment of existing buildings, compliant to actual regulations, often leads to airtightness and the consequent poor conditions for the occupants that could cause low productivity and even sickness. For this reaso...

Micromachined tunable Fabry-Pérot filters (μFPF) are key elements in a new class of miniature spectrometers and analyzers. Different groups all over the world are working on μFPF for spectral ranges from the visible up to the long wave infrared. In order to achieve a large tuning range, the filters are normally operated in the first interference or...

This paper presents a novel tunable infrared filter applying a subwavelength grating that substitutes the distributed Bragg reflectors (DBRs) in tunable Fabry-Perot (FP) filters to reduce cost and fabrication effort. It consists of uniformly arranged disc resonators which are made of 100 nm thick aluminum at a 200 nm Si3N4 membrane carrier that sta...

Refurbishing old buildings to make them energy efficient often leaves them so tightly sealed that indoor air quality suffers, with possible damaging consequences for human health and productivity. The EU-funded Cetieb research project is working to solve this problem by developing innovative ways of both monitoring and controlling the indoor enviro...

In this work, the applicability of charge controlled electrostatically tuneable optical filters is investigated. The filters are based on a Fabry-Pérot architecture, fabricated in a bulk micromachining process. Compared to surface micromachined devices, this design opens a path to higher optical performance due to the high planarity and low roughne...

In this work, an application of electrostatically tunable optical infrared filters in a closed-loop control system is presented. The filters are based on a Fabry-Pérot architecture, fabricated in a bulk micromachining process. Compared to surface micromachined devices, this design opens a path to higher optical performance due to the high planarity...

Zusammenfassung Mikrospektrometer besitzen ein großes Potenzial in der IR-Absorptionsspektroskopie. Im Beitrag werden durchstimmbare IR-Sensoren für das mittlere und langwellige Infrarot vorgestellt, welche auf pyroelektrischen Detektoren und mikromechanischen Fabry-Pérot-Filtern basieren. Ausgewählte Beispielapplikationen aus der medizinischen und...

As is generally known, miniature infrared spectrometers have great potential, e. g. for process and environmental analytics or in medical applications. Many efforts are being made to shrink conventional spectrometers, such as FTIR or grating based devices. A more rigorous approach for miniaturization is the use of MEMS technologies. Based on an est...

This paper reports on the application of sub-wavelength structured single layer reflectors in a Fabry-Perot-Interferometer (FPI) that are used in order to replace distributed Bragg reflectors (DBR). A pair of two-dimensional arrays of ring resonators was analyzed. A 100 nm thin Al layer is regularly patterned to form a meta-surface structure. It sh...

Das bei einer Verbrennung entstehende CO2 emittiert ein spezifisches Strahlungsspektrum bei etwa 4,3 μm Wellenlänge, das mit einem IR-Flammendetektor erfasst werden kann. Die marktüblichen Sensoren detektieren eine Flamme in einem festgelegten Gebiet (Field-of-View), ihre genaue Position kann jedoch nicht ermittelt werden. Der vorgestellte 3×3-Matr...

A tunable dual-band MEMS Fabry-Pérot filter for simultaneous use of the spectral ranges from 8 µm to 10.5 µm and from 4 µm to 5 µm is reported. A peak transmittance of at least 75 % and a FWHM of less than 200 nm were measured. The maximum control voltage is 41 V. Two movable reflector carriers compensate the influence of gravitational force on the...

A tunable IR filter based on a Fabry-Perot interferometer with two movable reflectors is reported. The infrared filter can be tuned over a wavelength range from 8 mum to 11 mum with voltages lower than 63 V. The FWHM bandwidth is lower than 200 nm and the peak transmittance is larger than 70 %. Simulation and practical shock test, both showed that...

In this paper we describe the design, the fabrication and the properties of tunable MEMS Fabry-Pérot (FP) filters for the long-wave infrared range (LWIR). Based on a mid-wave IR (MWIR) device, completely new optical and electro mechanical designs have to be used to extend the spectral range to the LWIR. A new set of optical thin films with low and...

Zusammenfassung In der IR-Absorptionsspektroskopie gibt es ein großes Potenzial für Mikrospektrometer z. B. für die Mehrkomponentenanalyse in der Gasmesstechnik. Es wird ein Mikrospektrometer für den Spektralbereich 3–5 μm vorgestellt, welches auf einem pyroelektrischen Detektor und einem MEMS-Fabry-Pérot-Filter (FPF) basiert. Die Gestaltung des op...

This work deals with the replacement of the reflection layer stacks by sub-wavelength structures, which form the cavity of Fabry-Perot-Interferometer (FPI) infrared filters. Periodically arranged metal ring resonators are investigated regarding reflectivity and sensitivity with respect to polarization angle by Finite Difference Method (FDM) analysi...

First results of a MEMS Fabry-Perot filter (FPF) for the spectral range of 8-11 mum are presented. Broad bandwidth and a low phase dispersion could be achieved by using new dielectric materials with an enhanced refractive index contrast and relatively simple reflector designs with a low number of layers. Different designs of the Bragg reflectors an...

In this paper we present basic designs, operation concepts and some application examples of a novel microspectrometer for the spectral range of 3-5mum, which is based on a pyroelectric detector with an integrated micromachined Fabry-Perot filter (FPF). We discuss the influence of different optical setups on the spectral resolution and the signal-to...

This paper reports design, fabrication and test results of a tunable pyroelectric detector with an integrated micromachined Fabry-Perot (FP) filter for gas analysis in the Mid-Wave Infrared (MWIR). The new approach is based on a bulk micromachined Fabry-Perot interferometer with an air cavity, which is electrostatically tuned. Various types of move...

This paper reviews design, performance and application of a wavelength-tunable pyroelectric detector for the spectral range of 3..5μm, based on a micromachined Fabry-Perot filter. Such devices have a large potential in the field of infrared absorption spectroscopy, particularly if multicomponent mixtures have to be analyzed. We present the operatio...

Multi-colour and tunable colour pyroelectric detectors are compared in respect of gas analysis. The key elements of the detectors are a beam splitter and a Fabry-perot filter respectively. The beam splitter are micromachined plates with pyramids or V-grooves with a pitch of 100…150 µm to ensure a homogeneous distribution of the radiation flux. Narr...

In this paper we present basic designs, operation concepts and some application examples of a novel microspectrometer for the spectral range of 3-5µm, which is based on a pyroelectric detector with an inte- grated micromachined Fabry-Perot filter (FPF). We discuss the influence of different optical setups on the spectral resolution and the signal-t...