LASER TYPES

Common types of lasers are:

• Semiconductor lasers (mostly laser diodes), electrically (or sometimes optically) pumped, efficiently generating very high output powers (but typically with poor beam quality ), or small powers with good spatial properties (e.g. for application in CD players), or pulses (e.g. for telecom applications) with very high repetition rates. Special types: quantum cascade lasers (for mid-infrared light), surface-emitting semiconductor lasers (VCSELs and VECSELs), the latter also being suitable for pulse generation with high powers.
• Solid-state lasers based on ion-doped crystals or glasses, pumped with discharge lamps or laser diodes, generating high output powers, or lower powers with very high beam quality, spectral purity, and/or stability (e.g. for measurement purposes), or ultrashort pulses with picosecond or femtosecond durations. Common gain media are Nd:YAG, Nd:YVO4, Nd:YLF, Nd:glass, Yb:YAG, Yb:glass, Er:Yb:glass, Ti:sapphire, Cr:YAG, Cr:LiSAF and Cr:LiCaF. A special type of ion-doped glass lasers are:
• Fiber lasers , based on optical glass fibers which are doped with some laser-active ions in the fiber core. Fiber lasers can achieve extremely high output powers (up to kilowatts) with good beam quality, allow for widely wavelength-tunable operation, narrow linewidth operation, etc.
• Gas lasers and excimer lasers , based on gases which are typically excited with electrical discharges.