APPLICATIONS

      Solid-state lasers are by far the most commonly used today. Low-powered infrared lasers are employed for many optical storage applications, including CD and DVD players. Visible laser diodes are also common and used for applications ranging from laser pointers and levels to scanning applications, often replacing helium–neon lasers. For storage applications a shorter wavelength is preferred since it can be used to yield a smaller spot size and hence increase the density of optical storage media. While short-wavelength diode lasers have recently been developed, their use in optical storage devices is relatively new. In addition to short-wavelength diodes, another alternative is the DPSS laser, in which a diode laser is used to pump a solid-state laser usually employing a YAG or vanadate crystal. High-powered arrays of semiconductor lasers allow the construction of DPSS lasers yielding second-harmonic powers in the tens-of-watts range, usually in the green region of the spectrum.