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Two-photon quantum well infrared photodetectors below 6 THz

: Franke, C.; Walther, Martin; Helm, M.; Schneider, H.


Infrared physics and technology 70 (2015), S.30-33
ISSN: 1350-4495
International Workshop on Quantum Structure Infrared Photodetectors (QSIP) <8, 2014, Santa Fe/NM>
Zeitschriftenaufsatz, Konferenzbeitrag
Fraunhofer IAF ()
quantum well infrared photodetector; Quantum Well Infrared Photodetector (QWIP); interferometric autocorrelation; nonlinear optic; two-photon absorption

Two-photon quantum well infrared photodetectors (QWIPs) are nonlinear detectors for the mid-infrared and terahertz regimes optimized for resonant two-photon absorption. Here we present first results on two-photon QWIP samples based on the GaAs/AIGaAs material system with intersubband energies between 25 and 12 meV (6-3 THz) confirmed by photocurrent spectra. The dark current showed large discontinuities, presumably caused by impact ionization. We performed interferometric autocorrelation experiments at the free-electron laser FELBE and observed nonlinear interferograms for all samples.