1. General

1.1 Variety of gas lasers

Gas lasers have a wide variety of characteristics (figure 1 ):

• wavelengths range from ultraviolet (excimer lasers) to visible to mid-infrared (CO ₂ lasers, emitted wavelength 10.6 µm);

• temporal aspects: unlike solid-state lasers, which are virtually all pulsed, gas lasers can be either pulsed only (excimers, copper vapor), continuous only (helium-neon, ionized argon), or (in the case of infrared-emitting lasers) continuous or pulsed. Pulsed lasers can...