Dr. Martin Walther Profile

Dr. Martin Walther

at Fraunhofer-IAF

SPIE Involvement:

Author

Publications (53)

Proceedings Article | 7 May 2019 Paper

Industrialization of type-II superlattice infrared detector technology at Fraunhofer IAF

M. Walther, V. Daumer, F. Rutz, T. Stadelmann, V. Klinger, A. Wörl, J. Niemasz, L. Kirste, R. Rehm

Proceedings Volume 11002, 110020C (2019) https://doi.org/10.1117/12.2518424

KEYWORDS: Sensors, Superlattices, Diodes, Infrared detectors, Gallium antimonide, Indium arsenide, Semiconducting wafers, Mercury cadmium telluride, Infrared sensors

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Proceedings Article | 23 May 2018 Paper

Type II superlattice infrared photodetector research at Fraunhofer IAF

T. Stadelmann, V. Daumer, V. Gramich, T. Hugger, L. Kirste, V. Klinger, N. Kohn, W. Luppold, R. Müller, J. Niemasz, R. Rehm, F. Rutz, J. Schmidt, M. Walther, M. Wauro, A. Wörl

Proceedings Volume 10624, 106240J (2018) https://doi.org/10.1117/12.2305116

KEYWORDS: Semiconducting wafers, Sensors, Photodiodes, Mid-IR, Heterojunctions, Long wavelength infrared, Photodetectors, Diodes, Superlattices, Infrared sensors

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Proceedings Article | 4 June 2015 Paper

Limiting dark current mechanisms in antimony-based superlattice infrared detectors for the long-wavelength infrared regime

Robert Rehm, Florian Lemke, Johannes Schmitz, Matthias Wauro, Martin Walther

Proceedings Volume 9451, 94510N (2015) https://doi.org/10.1117/12.2177091

KEYWORDS: Photodiodes, Stereolithography, Semiconducting wafers, Long wavelength infrared, Diodes, Superlattices, Diffusion, Resistance, Infrared detectors, Temperature metrology

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Proceedings Article | 13 May 2015 Paper

SWIR photodetector development at Fraunhofer IAF

F. Rutz, P. Kleinow, R. Aidam, H. Heussen, W. Bronner, A. Sieck, M. Walther

Proceedings Volume 9481, 948107 (2015) https://doi.org/10.1117/12.2177802

KEYWORDS: Avalanche photodetectors, Short wave infrared radiation, Indium gallium arsenide, Sensors, Cameras, Staring arrays, Photodetectors, PIN photodiodes, Doping, Imaging systems

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Proceedings Article | 7 October 2014 Paper

Optimization of InGaAs/InAlAs APDs for SWIR detection with demand for high gain and low breakdown voltage

P. Kleinow, F. Rutz, R. Aidam, W. Bronner, H. Heussen, M. Walther

Proceedings Volume 9249, 92490Y (2014) https://doi.org/10.1117/12.2067242

KEYWORDS: Short wave infrared radiation, Calibration, Cameras, Data acquisition, Imaging systems, Sensors, Data modeling, Hyperspectral imaging, Georeferencing, Image processing

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Proceedings Article | 24 June 2014 Paper

InAs/GaSb superlattice detectors for the long-wavelength infrared regime

Robert Rehm, Michael Masur, Johannes Schmitz, Martin Walther

Proceedings Volume 9070, 90700T (2014) https://doi.org/10.1117/12.2050438

KEYWORDS: Heterojunctions, Stereolithography, Superlattices, Long wavelength infrared, Sensors, Laser sintering, Doping, Gallium antimonide, Infrared sensors, Indium arsenide

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Proceedings Article | 24 June 2014 Paper

Development of bi-spectral InAs/GaSb type II superlattice image detectors

T. Stadelmann, A. Wörl, M. Wauro, V. Daumer, J. Niemasz, W. Luppold, T. Simon, M. Riedel, R. Rehm, M. Walther

Proceedings Volume 9070, 90700V (2014) https://doi.org/10.1117/12.2049951

KEYWORDS: Sensors, Image sensors, Superlattices, Mid-IR, Manufacturing, Diodes, Long wavelength infrared, Infrared sensors, Dielectrics, Photodiodes

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Proceedings Article | 31 January 2014 Paper

Infrared photodetector development at Fraunhofer IAF

F. Rutz, P. Kleinow, M. Walther, R. Aidam, W. Bronner, L. Kirste, J. Niemasz, R. Rehm, J. Schmitz, T. Stadelmann, M. Wauro, A. Wörl, A. Sieck, J. Ziegler

Proceedings Volume 8993, 89930W (2014) https://doi.org/10.1117/12.2039521

KEYWORDS: Sensors, Short wave infrared radiation, Indium gallium arsenide, Infrared radiation, Photodetectors, Avalanche photodetectors, Infrared detectors, Infrared sensors, Infrared photography, Long wavelength infrared

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Proceedings Article | 25 October 2013 Paper

InGaAs infrared detector development for SWIR imaging applications

F. Rutz, P. Kleinow, R. Aidam, W. Bronner, L. Kirste, M. Walther

Proceedings Volume 8896, 88960C (2013) https://doi.org/10.1117/12.2026879

KEYWORDS: Avalanche photodetectors, Indium gallium arsenide, Short wave infrared radiation, Sensors, Photodetectors, Detector development, Cameras, Diodes, Staring arrays, Infrared detectors

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Proceedings Article | 11 June 2013 Paper

Defects and noise in Type-II superlattice infrared detectors

Martin Walther, Andreas Wörl, Volker Daumer, Robert Rehm, Lutz Kirste, Frank Rutz, Johannes Schmitz

Proceedings Volume 8704, 87040U (2013) https://doi.org/10.1117/12.2015926

KEYWORDS: Diodes, Gallium antimonide, Etching, Palladium, Mid-IR, Data modeling, Superlattices, Semiconducting wafers, Photodiodes, Wet etching

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Proceedings Article | 4 February 2013 Paper

Noise in InAs/GaSb type-II superlattice photodiodes

R. Rehm, A. Wörl, M. Walther

Proceedings Volume 8631, 86311M (2013) https://doi.org/10.1117/12.2013854

KEYWORDS: Diodes, Mid-IR, Long wavelength infrared, Photodiodes, Stereolithography, Palladium, Data modeling, Superlattices, Electrons, Switching

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Proceedings Article | 21 May 2011 Paper

The development of 3[sup]rd[/sup] generation IR detectors at AIM

J. Ziegler, D. Eich, M. Mahlein, T. Schallenberg, R. Scheibner, J. Wendler, J. Wenisch, R. Wollrab, V. Daumer, R. Rehm, F. Rutz, M. Walther

Proceedings Volume 8012, 801237 (2011) https://doi.org/10.1117/12.883888

KEYWORDS: Sensors, Long wavelength infrared, Mid-IR, Staring arrays, Diodes, Medium wave, Readout integrated circuits, Gallium arsenide, Etching, Infrared detectors

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Proceedings Article | 21 May 2011 Paper

Current developments for type-II superlattice imaging systems

Frank Rutz, Robert Rehm, Martin Walther, Lutz Kirste, Michael Masur, Andreas Wörl, Johannes Schmitz, Matthias Wauro, Jasmin Niemasz, Ralf Scheibner, Johann Ziegler

Proceedings Volume 8012, 80120U (2011) https://doi.org/10.1117/12.883786

KEYWORDS: Gallium antimonide, Semiconducting wafers, Sensors, Stereolithography, Superlattices, Detector arrays, Thermography, Etching, Staring arrays, Mid-IR

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Proceedings Article | 24 January 2011 Paper

Defect density reduction in InAs/GaSb type II superlattice focal plane array infrared detectors

Martin Walther, Robert Rehm, Johannes Schmitz, Jasmin Niemasz, Frank Rutz, Andreas Wörl, Lutz Kirste, Ralf Scheibner, Joachim Wendler, Johann Ziegler

Proceedings Volume 7945, 79451N (2011) https://doi.org/10.1117/12.875159

KEYWORDS: Gallium antimonide, Sensors, Stereolithography, Semiconducting wafers, Infrared detectors, Staring arrays, Etching, Superlattices, Imaging systems, Cameras

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Proceedings Article | 4 May 2010 Paper

Type-II superlattices: the Fraunhofer perspective

Robert Rehm, Martin Walther, Johannes Schmitz, Frank Rutz, Andreas Wörl, Ralf Scheibner, Johann Ziegler

Proceedings Volume 7660, 76601G (2010) https://doi.org/10.1117/12.850172

KEYWORDS: Diodes, Gallium antimonide, Stereolithography, Sensors, Photodiodes, Detector arrays, Semiconducting wafers, Superlattices, Imaging systems, Infrared imaging

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Proceedings Article | 23 January 2010 Paper

InAs/GaSb type II superlattices for advanced 2nd and 3rd generation detectors

Martin Walther, Robert Rehm, Johannes Schmitz, Joachim Fleissner, Frank Rutz, Lutz Kirste, Ralf Scheibner, Joachim Wendler, Johann Ziegler

Proceedings Volume 7608, 76081Z (2010) https://doi.org/10.1117/12.842065

KEYWORDS: Gallium antimonide, Stereolithography, Sensors, Imaging systems, Superlattices, Thermography, Indium arsenide, Mid-IR, Cameras, Infrared detectors

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Proceedings Article | 24 September 2009 Paper

Advanced III/V quantum-structure devices for high performance infrared focal plane arrays

Robert Rehm, Martin Walther, Johannes Schmitz, Frank Rutz, Joachim Fleissner, Ralf Scheibner, Johann Ziegler

Proceedings Volume 7481, 74810E (2009) https://doi.org/10.1117/12.835153

KEYWORDS: Quantum well infrared photodetectors, Sensors, Stereolithography, Readout integrated circuits, Staring arrays, Superlattices, Infrared imaging, Infrared radiation, Silicon, Imaging systems

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Proceedings Article | 7 May 2009 Paper

InAs/GaSb superlattice focal plane array infrared detectors: manufacturing aspects

Frank Rutz, Robert Rehm, Johannes Schmitz, Joachim Fleissner, Martin Walther, Ralf Scheibner, Johann Ziegler

Proceedings Volume 7298, 72981R (2009) https://doi.org/10.1117/12.819090

KEYWORDS: Stereolithography, Sensors, Semiconducting wafers, Superlattices, Gallium antimonide, Cameras, Etching, Mid-IR, Staring arrays, Imaging systems

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Proceedings Article | 26 January 2009 Paper

Status of mid-infrared superlattice technology in Germany

Robert Rehm, Martin Walther, Johannes Schmitz, Frank Rutz, Joachim Fleissner, Ralf Scheibner, Johann Ziegler

Proceedings Volume 7222, 72220T (2009) https://doi.org/10.1117/12.809045

KEYWORDS: Superlattices, Sensors, Mid-IR, Stereolithography, Quantum efficiency, Semiconducting wafers, Cameras, Photodiodes, Absorption, Diodes

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Proceedings Article | 1 May 2008 Paper

Design optimization of superlattice type-II IR-detection modules with temporal signal coincidence in two spectral ranges

R. Breiter, H. Lutz, R. Scheibner, J. Wendler, K. Hofmann, J. Ziegler, M. Walther, R. Rehm

Proceedings Volume 6940, 69400B (2008) https://doi.org/10.1117/12.773918

KEYWORDS: Sensors, Stereolithography, Superlattices, Staring arrays, Readout integrated circuits, Quantum efficiency, Infrared sensors, Infrared detectors, Missiles, Quantum well infrared photodetectors

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Proceedings Article | 15 April 2008 Paper

Antimony-based superlattices for high-performance infrared imagers

Martin Walther, Robert Rehm, Johannes Schmitz, Frank Rutz, Joachim Fleissner, Johann Ziegler

Proceedings Volume 6940, 69400A (2008) https://doi.org/10.1117/12.777515

KEYWORDS: Stereolithography, Sensors, Diodes, Imaging systems, Mid-IR, Superlattices, Thermography, Cameras, Quantum efficiency, Gallium antimonide

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Proceedings Article | 14 May 2007 Paper

InAs/GaSb type-II short-period superlattices for advanced single and dual-color focal plane arrays

Martin Walther, Robert Rehm, Joachim Fleissner, Johannes Schmitz, Johann Ziegler, Wolfgang Cabanski, Rainer Breiter

Proceedings Volume 6542, 654206 (2007) https://doi.org/10.1117/12.719227

KEYWORDS: Sensors, Stereolithography, Staring arrays, Cameras, Gallium antimonide, Mid-IR, Superlattices, Imaging systems, Thermography, Indium arsenide

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Proceedings Article | 14 May 2007 Paper

Dual color IR detection modules, trends and applications

M. Münzberg, R. Breiter, W. Cabanski, K. Hofmann, H. Lutz, J. Wendler, J. Ziegler, R. Rehm, M. Walther

Proceedings Volume 6542, 654207 (2007) https://doi.org/10.1117/12.718798

KEYWORDS: Sensors, Superlattices, Stereolithography, Staring arrays, Quantum well infrared photodetectors, Missiles, Medium wave, Infrared detectors, Sniper detection, Mid-IR

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The 3rd generation of infrared (IR) detection modules is expected to provide advanced features like higher resolution 1024x1024 or 1280x720 pixels and/or new functions like multicolor or multi band capability, higher frame rates and better thermal resolution. This paper is intended to present the current status and trends at AIM on antimonide type II superlattices (SL) dual color detection module developments for ground and airborne applications in the high performance range, where rapidly changing scenes - like e.g. in case of missile warning applications for airborne platforms or ground based sniper detection systems - require temporal signal coincidence with integration times of typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The type II SL technology provides - similar to QWIP's - an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. IAF and AIM managed already to realize a dual color 384x288 IR module based on this technology. It combines spectral selective detection in the 3 - 4&mgr;m wavelength range and 4 - 5 &mgr;m wavelength range in each pixel with coincident integration in a 384x288x2 format and 40x40 &mgr;m² pitch. Excellent thermal resolution with NETD < 12 mK @ F/2, 2.8 ms for the longer wavelength range (red band) and NETD < 22 mK @ F/2, 2.8 ms for the shorter wavelength range (blue band) were reported. In the meantime a square design of 256x256x2 pixel with a reduced pitch of 30x30 &mgr;m² is in preparation. In this case with 2 Indium bumps per pixel and a third common contact for all pixels required for temporal coincidence is connected at the outer area of the array. The fill factor is approx. 65% for both wavelength ranges. The reduced size of the array enables the use of a smaller dewar with reduced cooling power and significantly reduced weight and broadens the scope of applications where weight and costs is essential. Design aspects and expected performances are discussed.

Proceedings Article | 8 February 2007 Paper

Autocorrelation measurements of the FELBE free-electron laser and photocurrent saturation study in two-photon QWIPs

H. Schneider, O. Drachenko, S. Winnerl, M. Helm, M. Walther

Proceedings Volume 6471, 64710T (2007) https://doi.org/10.1117/12.701895

KEYWORDS: Free electron lasers, Quantum well infrared photodetectors, Picosecond phenomena, Quantum wells, Absorption, Interferometry, Sensors, Surface plasmons, Temperature metrology, Nonlinear optics

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Proceedings Article | 7 September 2006 Paper

Second and third generation thermal imagers based on type-II superlattice photodiodes

Robert Rehm, Martin Walther, Johannes Schmitz, Joachim Fleißner, Johann Ziegler, Wolfgang Cabanski, Rainer Breiter

Proceedings Volume 6294, 629404 (2006) https://doi.org/10.1117/12.680495

KEYWORDS: Mid-IR, Sensors, Missiles, Stereolithography, Superlattices, Cameras, Staring arrays, Thermography, Imaging systems, Image processing

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Proceedings Article | 18 May 2006 Paper

Multispectral IR detection modules and applications

M. Münzberg, R. Breiter, W. Cabanski, H. Lutz, J. Wendler, J. Ziegler, R. Rehm, M. Walther

Proceedings Volume 6206, 620627 (2006) https://doi.org/10.1117/12.665467

KEYWORDS: Sensors, Quantum well infrared photodetectors, Stereolithography, Superlattices, Staring arrays, Spectroscopy, Missiles, Quantum efficiency, Readout integrated circuits, Infrared detectors

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This paper is intended to present firstly the current status at AIM on quantum well (QWIP) and antimonide superlattices (SL) detection modules for multi spectral ground and airborne applications in the high performance range i.e. for missile approach warning systems and secondly presents possibilities with long linear arrays i.e. 576x7 MCT to measure spectral selective in the 2 - 11μm wavelength range. QWIP and antimonide based superlattice (SL) modules are developed and produced in a work share between AIM and the Fraunhofer Institute for Applied Solid State Physics (IAF). The sensitive layers are manufactured by the IAF, hybridized and integrated to IDCA or camera level by AIM. In case of MCT based modules, all steps are done by AIM. QWIP dual band or dual color detectors provide good resolution as long as integration times in the order of 5-10ms can be tolerated. This is acceptable for all applications where no fast motions of the platform or the targets are to be expected. For spectral selective detection, a QWIP detector combining 3-5 μm (MWIR) and 8-10 μm (LWIR) detection in each pixel with coincident integration has been developed in a 384x288x2 format with 40 μm pitch. Excellent thermal resolution with NETD < 30 mK @ F/2, 6.8 ms for both peak wavelengths (4.8 μm and 8.0 μm) has been achieved. Thanks to the well established QWIP technology, the pixel outage rates even in these complex structures are well below 0.5% in both bands. The spectral cross talk between the two wavelength bands is equal or less than 1%. The substrate on the sensitive layer of the FPA was completely removed in this case and as a consequence the optical crosstalk in the array usually observed in QWIP arrays resulting in low MTF values was suppressed resulting in sharp image impression. For rapidly changing scenes - like e.g. in case of missile warning applications for airborne platforms - a material system with higher quantum efficiency is required to limit integration times to typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The type II SL technology provides - similar to QWIPs - an accurate engineering of sensitive layers by MBE with very good homogeneity and potentially good yield and resistivity against high temperature application i.e. under processing or storage. While promising results on single SL pixels have been reported since many years, so far no SL based detection module could be realized with reasonable performances. IAF and AIM last year managed to realize first most promising SL based detectors. Fully integrated IDCAs with a MWIR SL single color device with 256x256 pixels in 40 μm pitch have been integrated and tested. In the next step the pitch was reduced to 24μm in a 384x288 pixel configuration. With this design and further improved technology a very good pixel operabilities with very low cluster sizes (≤ 4 pixel) and performances with quantum efficiencies as high as known from MCT is reached in the meantime. A dual color device based on SL technology on the existing 384x288 read-out circuit (ROIC) as used in the dual band QWIP device is available. It combines spectral selective detection in the 3-4.1 μm wavelength range and 4.1-5 μm wavelength range in each pixel with coincident integration in a 384x288x2 format and 40 μm pitch. Excellent thermal resolution with NETD < 17 mK @ F/2, 2.8 ms for the longer wavelength range (red band) and NETD < 30 mK @ F/2, 2.8 ms for the shorter wavelength range (blue band) has been achieved. The pixel outage rates remains below 1% in both colors. The spectral cross talk of the red band to the blue band is estimated below 1%o which is important to reduce significantly the false alarm rate in missile approach warning systems as the primarily intended use of the dual color detector is. Real time analysis of gases, i.e. the detection of toxic or agent gases, by multi spectral detection in the IR used the characteristic infrared emission or absorption lines of different gas types. Spectroscopic systems consisting of a spectrometer with the need for large linear MCT array with small pixel sizes are used in this case. Possibilities are outlined to use long linear arrays, such as the 576x7 MCT detector, to perform spectral selective measurements in the 2-11μm wavelength range. For these applications a 576x7 MCT FPA is integrated in an open dewar cooler assy without window able to operate directly coupled in an evacuated and cooled spectrometer. The sensitivity of the array is consequently not limited by the transmission of a window for vacuum conservation in the full sensitive wavelength range of MCT up to the cut-off of 10.5 μm.

Proceedings Article | 17 May 2006 Paper

Bispectral thermal imaging with quantum-well infrared photodetectors and InAs/GaSb type-II superlattices

Robert Rehm, Martin Walther, Joachim Fleißner, Johannes Schmitz, Johann Ziegler, Wolfgang Cabanski, Rainer Breiter

Proceedings Volume 6206, 62060Y (2006) https://doi.org/10.1117/12.667627

KEYWORDS: Quantum well infrared photodetectors, Stereolithography, Sensors, Cameras, Medium wave, Thermography, Superlattices, Gallium antimonide, Infrared imaging, Infrared radiation

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Proceedings Article | 29 September 2005 Paper

InAs/GaSb superlattice focal plane arrays for high-resolution thermal imaging

Robert Rehm, Martin Walther, Johannes Schmitz, Joachim Fleißner, Frank Fuchs, Johann Ziegler, Wolfgang Cabanski

Proceedings Volume 5957, 595707 (2005) https://doi.org/10.1117/12.627054

KEYWORDS: Indium arsenide, Superlattices, Gallium antimonide, Quantum efficiency, Staring arrays, Sensors, Stereolithography, Cameras, Mid-IR, Thermography

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Proceedings Article | 31 May 2005 Paper

InAs/(GaIn)Sb short-period superlattices for focal plane arrays

Robert Rehm, Martin Walther, Johannes Schmitz, Joachim Fleissner, Frank Fuchs, Wolfgang Cabanski, Johann Ziegler

Proceedings Volume 5783, (2005) https://doi.org/10.1117/12.603420

KEYWORDS: Superlattices, Diodes, Staring arrays, Sensors, Antimony, Gallium, Gallium antimonide, Indium arsenide, Photodiodes, Mid-IR

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Proceedings Article | 31 May 2005 Paper

Third generation focal plane array IR detection modules and applications

W. Cabanski, M. Munzberg, W. Rode, J. Wendler, J. Ziegler, J. Fleissner, F. Fuchs, R. Rehm, J. Schmitz, H. Schneider, M. Walther

Proceedings Volume 5783, (2005) https://doi.org/10.1117/12.605818

KEYWORDS: Stereolithography, Sensors, Quantum well infrared photodetectors, Mid-IR, Staring arrays, Long wavelength infrared, Missiles, Superlattices, Readout integrated circuits, Absorption

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The 3rd generation of infrared (IR) detection modules is expected to provide advanced features like higher resolution 1024x1024 or 1280x720 pixels and/or new functions like multicolor or multi band capability, higher frame rates and better thermal resolution. This paper is intended to present the current status at AIM on quantum well (QWIP) and antimonide superlattices (SL) detection modules for ground and airborne applications in the high performance range. For spectral selective detection, a QWIP detector combining 3-5μm (MWIR) and 8-10μm (LWIR) detection in each pixel with coincident integration has been developed in a 384x288x2 format with 40 μm pitch. Excellent thermal resolution with NETD < 30mK @ F/2, 6.8 ms for both peak wavelengths (4.8 μm and 8.0 μm) has been achieved. Thanks to the well established QWIP technology, the pixel outage rates even in these complex structures are below 0.5% in both bands. QWIP dual band or dual color detectors provide good resolution as long as integration times in the order of 5-10ms can be tolerated. This is acceptable for all applications where no fast motions of the platform or the targets are to be expected. For rapidly changing scenes-like e.g. in case of missile warning applications for airborne platforms-a material system with higher quantum efficiency is required to limit integration times to typically 1ms. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The SL technology provides-similar to QWIP's-an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. While promising results on single SL pixels have been reported since many years, so far no SL based detection module could be realized. IAF and AIM last year managed to realize first most promising SL based detectors. Fully integrated IDCA's with a MWIR SL device with 256x256 pixels in 40µm pitch have been integrated and tested. The modules exhibit excellent thermal resolution of NETD<10mk @ F/2 and 5ms. Product improvement meanwhile allowed to reduce pixel outage rates below 1% i.e. down to a level as required for the military use of such detectors. Presently under development is therefore a dual color MWIR device based on SL technology and the existing 384x288 read out circuit (ROIC) used in the dual band QWIP device. This detector is primarily intended for the use in missile approach warning systems where the dual color capability significantly improves suppression of false alarms. Details of the modules and results of the electrooptical performance will be presented for the different items mentioned above.

Proceedings Article | 7 April 2005 Paper

Infrared focal plane array based on MWIR/LWIR dual-band QWIPs: detector optimization and array properties

Harald Schneider, Thomas Maier, Joachim Fleissner, Martin Walther, Peter Koidl, Gunter Weimann, Wolfgang Cabanski, Marcus Finck, Peter Menger, Werner Rode, Johann Ziegler

Proceedings Volume 5726, (2005) https://doi.org/10.1117/12.591546

KEYWORDS: Quantum well infrared photodetectors, Mid-IR, Staring arrays, Long wavelength infrared, Sensors, Thermography, Detector arrays, Readout integrated circuits, Gallium arsenide, Infrared radiation

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Proceedings Article | 30 August 2004 Paper

Third-generation focal plane array IR detection modules and applications

Wolfgang Cabanski, Kurt Eberhardt, Werner Rode, Joachim Wendler, Johann Ziegler, Joachim Fleissner, Frank Fuchs, Robert Rehm, Johannes Schmitz, Harald Schneider, Martin Walther

Proceedings Volume 5406, (2004) https://doi.org/10.1117/12.542186

KEYWORDS: Stereolithography, Quantum well infrared photodetectors, Sensors, Mid-IR, Long wavelength infrared, Staring arrays, Superlattices, Readout integrated circuits, Quantum efficiency, Infrared detectors

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The 3rd generation of infrared (IR) detection modules is expected to provide advanced features like higher resolution 1024x1024 or 1280x720 pixels and/or new functionalities like multicolor or multi band capability, higher frame rates and better thermal resolution. This paper is intended to present the current status at AIM on the Mercury Cadmium Telluride (MCT), quantum well (QWIP) and antimonide superlattices (SL) detection modules for ground and airborne applications in the high performance range. For high resolution a 1280x720 MCT device in the 3-5μm range (MWIR) is presently under development. For spectral selective detection, a QWIP detector combining MWIR and 8-10μm (LWIR) detection in each pixel has been developed in a 384x288x2 format with 40 μm pitch, NETD < 35mK @ F/2, 6,8 ms for both peak wavelengths (4.8 μm and 8.0 μm). The device provides synchronous integration of both bands for temporal and spatial coincidence of the events observed. QWIP dual band or dual color detectors provide good resolution as long as integration times in the order of 5-10ms can be tolerated. This is acceptable for all applications where no fast motions of the platform or the targets are to be expected. For rapidly changing scenes - like e.g. in case of missile warning applications for airborne platforms - a material system with higher quantum efficiency is required to limit integration times to typically 1ms. For this case, several companies work on molecular beam epitaxy (MBE) of MCT to have access to double or multi layer structures. AIM and IAF selected antimonide based type II superlattices (SL) for such kind of applications. The SL technology provides -- similar to QWIP's -- an accurate engineering of sensitive layers by MBE with very good homogeneity and yield. While promising results on single SL pixels have been reported since many years, so far no SL based detection module could be realized. Just recently, IAF and AIM managed to realize first most promising SL based detectors. Fully integrated IDCAs with a MWIR SL device with 256 x 256 pixels in 40 μm pitch have been integrated and tested. The modules exhibit excellent thermal resolution of NETD > 12 mk @ F/2 and 5 ms. The next step will now be to stabilize the technology and to start the development of a dual color MWIR device based on SL technology and the existing 384 x 288 read out circuit (ROIC) used in the dual band QWIP device.

Proceedings Article | 23 January 2003 Paper

High-resolution QWIP FPAs for the 8- to 12-µm and 3- to 5-µm regimes

Harald Schneider, Joachim Fleissner, Robert Rehm, Martin Walther, Wilfried Pletschen, Peter Koidl, Guenter Weimann, Johann Ziegler, Rainer Breiter, Wolfgang Cabanski

Proceedings Volume 4820, (2003) https://doi.org/10.1117/12.451319

KEYWORDS: Quantum well infrared photodetectors, Mid-IR, Staring arrays, Long wavelength infrared, Sensors, Quantum efficiency, Quantum wells, Cameras, Thermography, Diffraction gratings

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Proceedings Article | 6 August 2002 Paper

Multicolor and dual-band IR camera for missile warning and automatic target recognition

Rainer Breiter, Wolfgang Cabanski, Karl-Heinz Mauk, Werner Rode, Johann Ziegler, Harald Schneider, Martin Walther

Proceedings Volume 4718, (2002) https://doi.org/10.1117/12.478815

KEYWORDS: Missiles, Mid-IR, Sensors, Quantum well infrared photodetectors, Thermography, Cameras, Optical filters, Infrared cameras, Automatic target recognition, Long wavelength infrared

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Proceedings Article | 5 August 2002 Paper

QWIP LWIR cameras with NETD<10 mK and improved low-frequency drift for long observation time in medicine and research

Wolfgang Cabanski, Rainer Breiter, Werner Rode, Johann Ziegler, Harald Schneider, Martin Walther, Mark Fauci

Proceedings Volume 4721, (2002) https://doi.org/10.1117/12.478843

KEYWORDS: Quantum well infrared photodetectors, Cameras, Infrared imaging, Thermography, Medical imaging, Medicine, Staring arrays, Infrared radiation, Imaging systems, Infrared cameras

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Proceedings Article | 22 May 2002 Paper

Physics and applications of III-Sb-based type-I QW diode lasers

Carmen Mermelstein, M. Rattunde, J. Schmitz, Rudolf Kiefer, Martin Walther, Joachim Wagner

Proceedings Volume 4651, (2002) https://doi.org/10.1117/12.467945

KEYWORDS: Semiconductor lasers, Quantum wells, Aluminum, Laser damage threshold, Continuous wave operation, Temperature metrology, Methane, Absorption, Internal quantum efficiency, Waveguides

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Proceedings Article | 16 April 2002 Paper

High-power high-brightness ridge-waveguide tapered diode lasers at 940 nm

Marc Kelemen, Franz Rinner, Joseph Rogg, Nicolas Wiedmann, Rudolf Kiefer, Martin Walther, Michael Mikulla, Guenter Weimann

Proceedings Volume 4648, (2002) https://doi.org/10.1117/12.462644

KEYWORDS: Semiconductor lasers, High power lasers, Diffraction, Optical amplifiers, Optical pumping, Fiber amplifiers, Quantum wells, Mirrors, Reliability, Continuous wave operation

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Proceedings Article | 19 October 2001 Paper

High-power 980-nm semiconductor lasers by MBE

Michael Mikulla, Marc Kelemen, Martin Walther, Rudolf Kiefer, R. Moritz, Guenter Weimann

Proceedings Volume 4580, (2001) https://doi.org/10.1117/12.444955

KEYWORDS: Semiconductor lasers, High power lasers, Optical amplifiers, Reliability, Single mode fibers, Fiber couplers, Diffraction, Aluminum, Cladding, Diodes

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Proceedings Article | 10 October 2001 Paper

Third-generation focal plane array IR detection modules at AIM

Wolfgang Cabanski, Rainer Breiter, R. Koch, Karl-Heinz Mauk, Werner Rode, Johann Ziegler, Harald Schneider, Martin Walther, Reinhard Oelmaier

Proceedings Volume 4369, (2001) https://doi.org/10.1117/12.445314

KEYWORDS: Quantum well infrared photodetectors, Sensors, Mid-IR, Staring arrays, Nonuniformity corrections, Long wavelength infrared, Optical filters, Digital signal processing, Thermography, Electronics

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According to the common understanding, the 3rd generation of infrared (IR) detection modules is expected to provide advanced functionalities like more pixels, multicolor or multiband capability, higher frame rates and better thermal resolution. This paper is intended to present the present status at AIM on such technologies. A high speed device with 256 X 256 pixels in a 40μm pitch is designed to provide up to 800 Hz full frame rate with pixel rates as high as 80 Mpixels/s. The read out circuit is designed to stare while scan in a flash integration mode to allow nearly full frame integration for even 800 Hz frame rate. A miniaturized command and control electronics with 14 Bit deep digital output and a non uniformity correction board capable to take into account non linear self learning scene based correction models are developed together with the integrated detector cooler assembly (IDCA). As working horse for dual color/band capabilities, AIM has developed a sequential multi color module to provide customers with a flexible tool to analyze the pros and cons of spectral selective detection. The module is based on a 384x288 mercury cadmium telluride (MCT) detector available in the mid wave (MWIR) or long wave spectral band (LWIR). A rotating wheel with 4 facets for filters or microscanner plates provides spectral selectivity. AIM's programmable MVIP image processing is used for controlling the detector and for non uniformity correction. The MVIP allows set the integration time and NUC coefficients individually for each filter position for comparable performance to accurately evaluate the pay off of spectral selectivity in the IR. In parallel, a dual color detector FPA is under development. The FPA is realized as a MCT MWIR device, LWIR, however, is also doable. Dual color macro cells are realized with 192x192 pixels in a pitch of effectively 56 μm. The cell design provides, that both colors detect radiation from target points identical within the limited resolution of the optics to ensure coincident detection plus compensates the significant variation in photon flux of the different colors to output the analog signal at approximately the same level for good thermal resolution and correctability. The photovoltaic device is realized using AIM's mature liquid phase epitaxy. Since quantum well (QWIP) technology has proven state of the art results based on a well established material system, AIM is heading for QWIP devices for most affordable solutions in the MWIR/LWIR dual band applications. A summary of state of the art results achieved so far as basis for a QWIP dual band detector is presented.

Proceedings Article | 12 June 2001 Paper

Responsivity and gain in InGaAs/GaAs-QWIPs and GaAs/AlGaAs-QWIPs: a comparative study

Robert Rehm, Harald Schneider, K. Schwarz, Martin Walther, Peter Koidl, Guenter Weimann

Proceedings Volume 4288, (2001) https://doi.org/10.1117/12.429424

KEYWORDS: Quantum well infrared photodetectors, Gallium arsenide, Sensors, Doping, Quantum wells, Quantum efficiency, Mirrors, Solids, Black bodies, Imaging systems

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Proceedings Article | 6 June 2001 Paper

High-brightness laser diodes using angular filtering by total reflection

Joseph Rogg, Konstantin Boucke, Marc Kelemen, Franz Rinner, Wilfried Pletschen, Rudolf Kiefer, Martin Walther, Michael Mikulla, Reinhart Poprawe, Guenter Weimann

Proceedings Volume 4287, (2001) https://doi.org/10.1117/12.429801

KEYWORDS: Semiconductor lasers, Mirrors, Optical filters, Near field, High power lasers, Reflectivity, Diffusion, Refractive index, Reflection, Solids

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Proceedings Article | 15 December 2000 Paper

Low-noise QWIPs for FPA sensors with high thermal resolution

Harald Schneider, Martin Walther, Joachim Fleissner, Robert Rehm, E. Diwo, K. Schwarz, Peter Koidl, Guenter Weimann, Johann Ziegler, Rainer Breiter, Wolfgang Cabanski

Proceedings Volume 4130, (2000) https://doi.org/10.1117/12.409877

KEYWORDS: Quantum well infrared photodetectors, Sensors, Staring arrays, Cameras, Imaging systems, Quantum wells, Long wavelength infrared, Electrons, Gallium arsenide, Infrared sensors

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Proceedings Article | 17 July 2000 Paper

High-resolution focal plane array IR detection modules and digital signal processing technologies at AIM

Wolfgang Cabanski, Rainer Breiter, R. Koch, Karl-Heinz Mauk, Werner Rode, Johann Ziegler, Kurt Eberhardt, Reinhard Oelmaier, Harald Schneider, Martin Walther

Proceedings Volume 4028, (2000) https://doi.org/10.1117/12.391723

KEYWORDS: Quantum well infrared photodetectors, Mid-IR, Image filtering, Staring arrays, Sensors, Digital signal processing, Optical filters, Filtering (signal processing), Infrared imaging, Long wavelength infrared

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Full video format focal plane array (FPA) modules with up to 640 X 512 pixels have been developed for high resolution imaging applications in either mercury cadmium telluride (MCT) mid wave (MWIR) infrared (IR) or platinum silicide (PtSi) and quantum well infrared photodetector (QWIP) technology as low cost alternatives to MCT for high performance IR imaging in the MWIR or long wave spectral band (LWIR). For the QWIP's, a new photovoltaic technology was introduced for improved NETD performance and higher dynamic range. MCT units provide fast frame rates > 100 Hz together with state of the art thermal resolution NETD < 20 mK for short snapshot integration times of typically 2 ms. PtSi and QWIP modules are usually operated in a rolling frame integration mode with frame rates of 30 - 60 Hz and provide thermal resolutions of NETD < 80 mK for PtSi and NETD < 20 mK for QWIP, respectively. Due to the lower quantum efficiency compared to MCT, however, the integration time is typically chosen to be as long 10 - 20 ms. The heat load of the integrated detector cooler assemblies (IDCAs) could be reduced to an amount as low, that a 1 W split liner cooler provides sufficient cooling power to operate the modules -- including the QWIP with 60 K operation temperature -- at ambient temperatures up to 65 degrees Celsius. Miniaturized command/control electronics (CCE) available for all modules provide a standardized digital interface, with 14 bit analogue to digital conversion for state to the art correctability, access to highly dynamic scenes without any loss of information and simplified exchangeability of the units. New modular image processing hardware platforms and software for image visualization and nonuniformity correction including scene based self learning algorithms had to be developed to accomplish for the high data rates of up to 18 M pixels/s with 14-bit deep data, allowing to take into account nonlinear effects to access the full NETD by accurate reduction of residual fixed pattern noise. The main features of these modules are summarized together with measured performance data for long range detection systems with moderately fast to slow F-numbers like F/2.0 - F/3.5. An outlook shows most recent activities at AIM, heading for multicolor and faster frame rate detector modules based on MCT devices.

Proceedings Article | 30 March 2000 Paper

High-performance focal plane array modules for research and development

Rainer Breiter, Wolfgang Cabanski, Johann Ziegler, Martin Walther, Harald Schneider

Proceedings Volume 4020, (2000) https://doi.org/10.1117/12.381558

KEYWORDS: Quantum well infrared photodetectors, Thermography, Staring arrays, Image processing, Mid-IR, Sensors, Digital signal processing, Analog electronics, Nonuniformity corrections, Cameras

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Proceedings Article | 29 March 2000 Paper

267-W cw AlGaAs/GaInAs diode laser bars

Juergen Braunstein, Michael Mikulla, Rudolf Kiefer, Martin Walther, Juergen Jandeleit, Wolfgang Brandenburg, Peter Loosen, Reinhart Poprawe, Guenter Weimann

Proceedings Volume 3945, (2000) https://doi.org/10.1117/12.380551

KEYWORDS: Semiconductor lasers, High power lasers, Resistance, Sensors, Lab on a chip, Electro optics, Temperature metrology, Continuous wave operation, Copper

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Proceedings Article | 26 October 1999 Paper

InAs/Ga1-xInxSb infrared superlattice diodes: correlation between surface morphology and electrical performance

Frank Fuchs, L. Buerkle, Wilfried Pletschen, J. Schmitz, Martin Walther, H. Gullich, N. Herres, Sabine Mueller

Proceedings Volume 3794, (1999) https://doi.org/10.1117/12.366728

KEYWORDS: Diodes, Atomic force microscopy, Gallium antimonide, Superlattices, X-ray diffraction, Laser sintering, Infrared radiation, Stereolithography, Infrared spectroscopy, Surface roughness

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Proceedings Article | 26 October 1999 Paper

High-speed photocurrent in quantum well infrared photodetectors

Harald Schneider, Peter Koidl, Martin Walther, Z. Lao, Michael Schlechtweg

Proceedings Volume 3794, (1999) https://doi.org/10.1117/12.366729

KEYWORDS: Quantum well infrared photodetectors, Picosecond phenomena, Heterodyning, Sensors, Amplifiers, Gallium arsenide, Infrared radiation, Signal detection, Field effect transistors, Optical amplifiers

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Proceedings Article | 26 July 1999 Paper

High-resolution QWIP and MCT FPA modules at AIM

Rainer Breiter, Wolfgang Cabanski, R. Koch, Werner Rode, Johann Ziegler, Kurt Eberhardt, Reinhard Oelmaier, Martin Walther

Proceedings Volume 3698, (1999) https://doi.org/10.1117/12.354541

KEYWORDS: Quantum well infrared photodetectors, Mid-IR, Staring arrays, Long wavelength infrared, Electronics, Photovoltaics, Sensors, Capacitance, Mercury cadmium telluride, Analog electronics

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Proceedings Article | 1 April 1999 Paper

High-power InAlGaAs laser diodes with high efficiency at 980 nm

Michael Mikulla, Alexis Schmitt, Martin Walther, Rudolf Kiefer, R. Moritz, Sabine Mueller, R. Sah, Juergen Braunstein, Guenter Weimann

Proceedings Volume 3628, (1999) https://doi.org/10.1117/12.344542

KEYWORDS: Semiconductor lasers, High power lasers, Diodes, Reliability, Broad area laser diodes, Continuous wave operation, Cladding, Aluminum, Quantum wells

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Proceedings Article | 26 October 1998 Paper

III-V semiconductor quantum well and superlattice detectors

Martin Walther, Frank Fuchs, Harald Schneider, Joachim Fleissner, J. Schmitz, Wilfried Pletschen, Juergen Braunstein, Johann Ziegler, Wolfgang Cabanski, Peter Koidl, Guenter Weimann

Proceedings Volume 3436, (1998) https://doi.org/10.1117/12.328032

KEYWORDS: Sensors, Staring arrays, Quantum well infrared photodetectors, Cameras, Gallium arsenide, Quantum wells, Diodes, Thermography, Long wavelength infrared, Chemical elements

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Proceedings Article | 8 April 1998 Paper

InAs/Ga1-xInxSb infrared superlattice photodiodes for infrared detection

Frank Fuchs, U. Weimar, E. Ahlswede, Wilfried Pletschen, J. Schmitz, Martin Walther

Proceedings Volume 3287, (1998) https://doi.org/10.1117/12.304477

KEYWORDS: Diodes, Stereolithography, Magnetism, Doping, Superlattices, Photodiodes, Indium arsenide, Infrared photography, Infrared radiation, Infrared detectors

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Proceedings Article | 7 April 1998 Paper

Improved beam quality for high-power tapered laser diodes with LMG (low-modal-gain) epitaxial layer structures

Michael Mikulla, Alexis Schmitt, Pierre Chazan, A. Wetzel, Martin Walther, Rudolf Kiefer, Wilfried Pletschen, Juergen Braunstein, Guenter Weimann

Proceedings Volume 3284, (1998) https://doi.org/10.1117/12.304433

KEYWORDS: Semiconductor lasers, Active optics, High power lasers, Oscillators, Diffraction, Hole burning spectroscopy, Continuous wave operation, Diodes, Optical simulations, Waveguides

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Proceedings Article | 1 August 1990 Paper

Switching characteristics of SEEDs with integrated Fabry-Perot resonator

Martin Walther, Karl Ebeling

Proceedings Volume 1280, (1990) https://doi.org/10.1117/12.20649

KEYWORDS: Switching, Reflectivity, Fabry–Perot interferometers, Bistability, Resonators, Modulation, Modulators, Reflectors, High speed photonics, Optical signal processing

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