Abstract

A semiconductor injection laser that differs in a fundamental way from diode lasers has been demonstrated. It is built out of quantum semiconductor structures that were grown by molecular beam epitaxy and designed by band structure engineering. Electrons streaming down a potential staircase sequentially emit photons at the steps. The steps consist of coupled quantum wells in which population inversion between discrete conduction band excited states is achieved by control of tunneling. A strong narrowing of the emission spectrum, above threshold, provides direct evidence of laser action at a wavelength of 4.2 micrometers with peak powers in excess of 8 milliwatts in pulsed operation. In quantum cascade lasers, the wavelength, entirely determined by quantum confinement, can be tailored from the mid-infrared to the submillimeter wave region in the same heterostructure material.

Keywords

LaserPopulation inversionOptoelectronicsQuantum tunnellingQuantum wellCascadeSemiconductor laser theoryQuantum cascade laserQuantum dot laserPhysicsExcited stateMolecular beam epitaxyDiodeElectronWavelengthQuantumHeterojunctionSemiconductorOpticsMaterials scienceAtomic physicsChemistryNanotechnologyEpitaxyQuantum mechanics

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Publication Info

Year
1994
Type
article
Volume
264
Issue
5158
Pages
553-556
Citations
4367
Access
Closed

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Cite This

Jérôme Faist, Federico Capasso, Deborah L. Sivco et al. (1994). Quantum Cascade Laser. Science , 264 (5158) , 553-556. https://doi.org/10.1126/science.264.5158.553

Identifiers

DOI
10.1126/science.264.5158.553