Laser Diode Optics

Laser diode or Diode laser is a semiconductor device similar to a light-emitting diode in which a diode-pumped directly with electrical current can create lasing conditions at the diode's junction. Laser diodes can directly convert electrical energy into light. Driven by voltage, the doped p-n-transition allows for the recombination of an electron with a hole. Due to the drop of the electron from a higher energy level to a lower one, radiation, in the form of an emitted photon is generated. This is a spontaneous emission. Stimulated emission can be produced when the process is continued and further generate light with the same phase, coherence, and wavelength.

Typical Applications

Laser diodes can be arrayed to produce very high power outputs, continuous wave or pulsed. Such arrays may be used to efficiently pump solid-state lasers for high average power drilling, burning or for inertial confinement fusion.

Telecommunications, scanning, and spectrometry

Medical Uses

COE optics often supply the following common wavelengths and uses.

Visible light

•    405 nm – InGaN blue-violet laser, in Blu-ray Disc and HD DVD drives
•    635 nm – AlGaInP better red laser pointers, same power subjectively twice as bright as 650 nm
•    650–660 nm – GaInP/AlGaInP CD and DVD drives, cheap red laser pointers
•    670 nm – AlGaInP bar code readers, first diode laser pointers (now obsolete, replaced by brighter 650 nm and 671 nm DPSS)

Infrared

•    760 nm – AlGaInP gas sensing: O2
•    785 nm – GaAlAs Compact Disc drives
•    808 nm – GaAlAs pumps in DPSS Nd:YAG lasers (e.g., in green laser pointers or as arrays in higher-powered lasers)
•    980 nm – InGaAs pump for optical amplifiers, for Yb:YAG DPSS lasers
•    1,064 nm – AlGaAs fiber-optic communication, DPSS laser pump frequency
•    1,310 nm – InGaAsP, InGaAsN fiber-optic communication
•    1,480 nm – InGaAsP pump for optical amplifiers
•    1,512 nm – InGaAsP gas sensing: NH3
•    1,550 nm – InGaAsP, InGaAsNSb fiber-optic communication