Intersubband terahertz lasers using four-level asymmetric quantum wells

P. Kinsler, P. Harrison, R. W. Kelsall

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


We demonstrate the potential for laser operation at far-infrared wavelengths (30-300 μm, 1-10 THz) by using intersubband emission in four-level GaAs/AlGaAs asymmetric (stepped) quantum wells. Achieving population inversion in these devices depends critically on the lifetimes of the nonradiative intersubband transitions, and so we have performed detailed calculations of electron-electron and electron-phonon scattering rates. Our four-subband structures show potential for the realization of room temperature lasing, unlike previously considered three-subband structures which did not give population inversions except at impractically low electron densities and temperatures. Auger-type electron-electron interactions involving the highly populated ground subband effectively destroyed the population inversion in three level systems, but in these four subband structures the inversion is maintained by strong phonon-mediated depopulation of the lower laser level. The largest population inversions are calculated at low temperatures (<30 K), but for the structures with higher emission energies, room temperature (300 K) operation is also predicted.

Original languageEnglish
Pages (from-to)23-28
Number of pages6
JournalJournal of Applied Physics
Issue number1
Early online date16 Dec 1998
Publication statusPublished - 1 Jan 1999
Externally publishedYes


Dive into the research topics of 'Intersubband terahertz lasers using four-level asymmetric quantum wells'. Together they form a unique fingerprint.

Cite this