Abstract
Intersubband stimulated emission under optical pumping has been observed in the conduction band of GaAs-AlGaAs quantum wells. The asymmetric coupled quantum wells which exhibit three conduction bound levels are designed to exhibit population inversion under optical pumping. An optical excitation at λ=9.2 μm is used to bleach the absorption between the ground and second excited subband. The population inversion between excited subbands is pumped and probed on a picosecond time scale by a tunable two-color free-electron laser. The stimulated amplification is studied at low temperature in infrared waveguides as a function of the waveguide length and of the probe wavelength. A stimulated gain ≈80cm-1 is measured at 12.5 μm in agreement with calculations.
Original language | English (US) |
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Pages (from-to) | 3197-3199 |
Number of pages | 3 |
Journal | Applied Physics Letters |
Volume | 70 |
Issue number | 24 |
DOIs | |
State | Published - Jun 16 1997 |
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)