Quantum Cascade Lasers Feature Summary
- From Physics Research
Quantum Cascade Lasers
- The image above shows a quantum cascade laser captured by a camera that images infrared light. The laser light is the small dot in the middle of the round window. The laser itself--behind the window--is kept at a temperature of -193° C, just above the temperature of liquid nitrogen.
Quantum cascade lasers work like this:
- In a thin slice of a semiconductor, an electron can occupy discrete energy levels.
- When an electron moves from a higher level to a lower level, a photon is emitted.
- If many thin slices of semiconductor are stacked together, the electron can cascade from one to another, emitting a photon of the same frequency in each slice. These photons form the laser beam.
- To learn more, see Quantum Cascade Lasers.
- image credit: Fatima Toor; image source; larger image
- Image URL:
- http://www.compadre.org/Informal/images/features/quantum laser -large.jpg
- November 1, 2010 - December 1, 2010