Quantum Cascade Laser

• DOI: 10.1126/science.264.5158.553
• Publication Date: 2006-10-06T00:01:25Z
• Authors: Jerome Faist; Federico Capasso; Deborah L. Sivco; Carlo Sirtori; Albert L. Hutchinson; Alfred Y. Cho
• Keywords: Population inversion; Quantum cascade laser

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