In the Spring of 1996, the Bell Labs researchers demonstrated the first room temperature operation of a high power quantum cascade laser. The second generation QCL can produce approximately 200 milliwatts of power at 77 degrees Fahrenheit, 298K and 100 milliwatts at 127 Fahrenheit. This has important implications in the field of spectral analysis. This process consists of passing laser light through a gas and measuring how much of the light is absorbed. This information can tell us the concentration of a substance, say a pollutant or factory emission, in air.
Every molecule absorbs a specific type of light.
The QCL allows us to reach these frequencies and as a result, could have tremendous impact on the field of environmental control, manufacturing and law enforcement. This frequency range also includes the active bands for heat sensors such as the type used in infrared surface to air missiles. Quantum cascade laser technology could be applied as an electronic countermeasures system for the American military. Because cascade lasers produce a photon of light at every active region, one electron in the Bell Labs laser can produce as many as 25 photons. A conventional semiconductor laser producing light by electron hole pair recombination can only produce one photon per electron.