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.
Vandermeiren, W, Stiens, J, De Tandt, C, Shkerdin, G, Kotov, V, Borghs, G, Muys, P & Vounckx, R 2010, Thermal cross-talk reduction in IR thermo-electric photodetectors by lock-in method: 4D numerical simulations and experimental verification. in B Witzigmann, F Henneberger, Y Arakawa & M Osinski (eds), Proceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII. vol. 7597, Proceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII, SPIE, Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet, Stockholm, Sweden, 21/09/09.
Vandermeiren, W., Stiens, J., De Tandt, C., Shkerdin, G., Kotov, V., Borghs, G., Muys, P., & Vounckx, R. (2010). Thermal cross-talk reduction in IR thermo-electric photodetectors by lock-in method: 4D numerical simulations and experimental verification. In B. Witzigmann, F. Henneberger, Y. Arakawa, & M. Osinski (Eds.), Proceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII (Vol. 7597). (Proceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII). SPIE.
@inproceedings{821690d34fbe4b6b8da9a150abbe393c,
title = "Thermal cross-talk reduction in IR thermo-electric photodetectors by lock-in method: 4D numerical simulations and experimental verification",
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.",
keywords = "Seebeck, infrared photodetector, FEM simulations, lock-in method, cross-talk reduction",
author = "Werner Vandermeiren and Johan Stiens and {De Tandt}, Cathleen and Gennady Shkerdin and Vladimir Kotov and Gustaaf Borghs and Peter Muys and Roger Vounckx",
note = "Bernd Witzigmann; Fritz Henneberger; Yasuhiko Arakawa; Marek Osinski; Finds and Results from the Swedish Cyprus Expedition: A Gender Perspective at the Medelhavsmuseet ; Conference date: 21-09-2009 Through 25-09-2009",
year = "2010",
month = mar,
day = "11",
language = "English",
isbn = "978-0-8194-7993-8",
volume = "7597",
series = "Proceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII",
publisher = "SPIE",
editor = "Bernd Witzigmann and Fritz Henneberger and Yasuhiko Arakawa and Marek Osinski",
booktitle = "Proceedings of the SPIE - Physics and Simulation of Optoelectronic Devices XVIII",
address = "United States",
}