What lasers have historic interest but are seldom used?

The argon laser (488 nm, 514 nm), was one of the first dermatologic lasers. This is seldom used because of scarring issues. The krypton laser generates dual wavelengths: 520-nm (green) and 568-nm (yellow) light. The continuouswave thermal nature of the laser caused too much surface heating. Copper vapor lasers generate dual wavelengths of 511 nm (green light) and 578 nm (yellow light). These lasers are not currently used. There was a pulsed dye pigment lesion laser with a wavelength of 504 nm. This laser effectively treated surface pigmentation but was mechanically unsound and is no longer available (Table 54-2).