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HL: Halbleiterphysik

HL 39: Hauptvortrag

HL 39.1: Invited Talk

Friday, March 30, 2001, 10:00–10:45, S2

Quantum Cascade Lasers: Recent Results — •Claire Gmachl, Alessandro Tredicucci, Ruedeger Koehler, Hock M. Ng, Federico Capasso, Albert L. Hutchinson, Deborah L. Sivco, and Alfred Y. Cho — Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974

Intersubband Quantum Cascade (QC) lasers are a rapidly evolving technology for mid-infrared semiconductor lasers. Their strength lies in their wavelength tailorability, intrinsic high power, and design potential. We have fabricated high performance, short wavelength (4.6 µm) lasers using strain-compensated InGaAs/AlInAs multiple quantum wells. Long wavelength (16.2 µm) QC-DFB lasers are based on Bragg-modulated surface plasmon waveguides. In collaborations with expert spectroscopists QC-DFB lasers are being tested in realistic gas-sensing applications, in particular for wavelengths around 5 and 8 µm. Recently, there is considerable interest in extending the wavelength range of QC-lasers. As a first step towards shorter wavelength, we have investigated intersubband optical absorption in narrow GaN/AlGaN quantum wells. The samples were grown by molecular beam epitaxy on sapphire substrate. They showed peak absorption wavelengths as short as 1.4 µm. The latter is important as it demonstrates that intersubband transitions in the GaN/AlGaN material system can be used to access the communications wavelength range.