Thermal cross-talk reduction in IR thermo-electric photodetectors by lock-in method: 4D numerical simulations and experimental verification

Werner Vandermeiren, Johan Stiens, Cathleen De Tandt, Gennady Shkerdin, Vladimir Kotov, Gustaaf Borghs, Peter Muys, Roger Vounckx

Research output: Chapter in Book/Report/Conference proceedingConference paper

1 Citation (Scopus)

Abstract

Laser induced temperature distributions inside doped semiconductor materials are used to derive laser beam profiles by means of the thermo-electric Seebeck effect. Thermal diffusion will lead to a discrepancy between the optical intensity profile of the laser beam and the measured temperature distribution inside the semiconductor. An advanced numerical 4D finite element model describing the laser induced spatial temperature distribution in function of time in a layered GaAs based structure was developed in Comsol Multiphysics. Non-linearities as the temperature dependence of the absorption coefficient, the thermal conductivity and the Seebeck coefficient were taken into account. This model was used to investigate the optical chopper frequency dependence on the spatial thermal cross-talk level and the responsivity near the illuminated surface of the detector structure. It was shown that the frequency dependent cross-talk level can be reduced significantly by applying short chopping periods due to the dependence of the thermal diffusion length on the frequency. The thermal cross-talk is reduced to -21 dB and -38.6 dB for the first and second neighboring pixel respectively for a lock-in frequency of 140 Hz. Experimental results of the spatial thermal cross-talk level and the responsivity were compared with simulations and satisfactory agreements between both were achieved. High power CO2 laser profile measurements obtained with our thermo-electric detector and a commercially available Primes detector were compared.
Original languageEnglish
Title of host publicationProceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII
EditorsBernd Witzigmann, Fritz Henneberger, Yasuhiko Arakawa, Marek Osinski
PublisherSPIE
Number of pages9
Volume7597
ISBN (Print)978-0-8194-7993-8
Publication statusPublished - 11 Mar 2010
EventFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet - Stockholm, Sweden
Duration: 21 Sep 200925 Sep 2009

Publication series

NameProceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII

Conference

ConferenceFinds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet
CountrySweden
CityStockholm
Period21/09/0925/09/09

Bibliographical note

Bernd Witzigmann; Fritz Henneberger; Yasuhiko Arakawa; Marek Osinski

Keywords

  • Seebeck
  • infrared photodetector
  • FEM simulations
  • lock-in method
  • cross-talk reduction

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