In the case of a diode laser,light from diodes is optically focused into a laser beam. The diode laser is 3 to 10 times more efficient than the CO and Nd:YAG lasers. However, the potential output density of the diode lasers is lower.
Solid-state laser in which lasing is achieved by passing an injection current through the active region of a semiconductor across the p–n junction. Operating in the infrared spectral region, 2.7–30 μm, makes diode lasers particularly useful for the measurement of certain atmospheric trace gases such as nitrous oxide, carbon monoxide, or formaldehyde. Reid, J., J. Shewchun, B. K. Garside, and E. A. Ballik, 1978: High sensitivity pollution detection employing tunable diode lasers. Appl. Optics, 17, 300–307.