Quantum Cascade Laser
Quantum cascade lasers (QCLs) are semiconductor lasers that emit in the mid- to far-infrared portion of the electromagnetic spectrum and were first demonstrated by Jerome Faist, Federico Capasso, Deborah Sivco, Carlo Sirtori, Albert Hutchinson, and Alfred Cho at Bell Laboratories in 1994.
Unlike typical interband semiconductor lasers that emit electromagnetic radiation through the recombination of electron–hole pairs across the material band gap, QCLs are unipolar and laser emission is achieved through the use of intersubband transitions in a repeated stack of semiconductor multiple quantum well heterostructures, an idea first proposed in the paper "Possibility of amplification of electromagnetic waves in a semiconductor with a superlattice" by R.F. Kazarinov and R.A. Suris in 1971.
Read more about Quantum Cascade Laser: Intersubband Vs. Interband Transitions, Material Systems, Emission Wavelengths, Optical Waveguides, Laser Types, Growth, Applications
Famous quotes containing the words quantum and/or cascade:
“The receipt to make a speaker, and an applauded one too, is short and easy.—Take of common sense quantum sufficit, add a little application to the rules and orders of the House, throw obvious thoughts in a new light, and make up the whole with a large quantity of purity, correctness, and elegancy of style.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
““End of tomorrow.
Don’t try to start the car or look deeper
Into the eternal wimpling of the sky: luster
On luster, transparency floated onto the topmost layer
Until the whole thing overflows like a silver
Wedding cake or Christmas tree, in a cascade of tears.””
—John Ashbery (b. 1927)