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HL: Fachverband Halbleiterphysik

HL 43: Poster Session: Quantum Dots and Wires - Preparation and Characterization / Devices (incl. Laser) / Ultrafast Phenomena

HL 43.24: Poster

Tuesday, March 27, 2012, 09:30–12:30, Poster D

Intersubband dynamics in two-photon quantum well infrared photodetectors — •Carsten Franke¹, Harald Schneider¹, Jérôme Faist², and H. C. Liu³ — ¹Helmholtz-Zentrum Dresden- Rossendorf, 01314 Dresden, Germany — ²ETH Zürich, 8093 Zürich, Switzerland — ³Shanghai Jiao Tong University, 200240 Shanghai, China

Two-photon quantum well infrared photodetectors (QWIPs) are interesting nonlinear devices for autocorrelation measurements in the mid-infrared and THz-regime. Here we investigate two-photon QWIPs in the mid-infrared with absorption wavelengths at around six microns, based on the material systems InGaAs/AlGaAs on GaAs and GaInAs/AlInAs on InP. We study the intersubband relaxation dynamics by interferometric autocorrelation. To create the necessary mid infrared sub-picosecond pulses, we use a regenerative amplifier system with subsequent wavelength conversion by optical parametric amplification and difference frequency generation. With this we can create mid-infrared laser pulses shorter than 200 fs tunable from 3 to 10 µm. For the intersubband relaxation time we determined values between 590 and 730 fs.