Blue Laser

A blue laser is a laser that emits electromagnetic radiation at a wavelength of between 360 and 480 nanometres, which the human eye sees as blue or violet. Diode lasers which emit light at 445 nm are becoming popular as handheld lasers. Lasers emitting wavelengths below 445 nm appear violet to the human eye, a distinctly different color. This is true, for example, of the most commercially common "blue" lasers, the diode lasers used in Blu-ray applications, which emit 405 nm violet light, which is a short enough wavelength to cause fluorescence in some chemicals, in the same way as radiation further into the ultraviolet ("black light") does. Light of a shorter wavelength than 400 nm is classified as ultraviolet.

The class of blue lasers are frequently semiconductor laser diodes based on gallium(III) nitride (GaN; violet color) or indium gallium nitride (often true blue in color, but also able to produce other colors). Both blue and violet lasers can also be constructed using frequency-doubling of infrared laser wavelengths from diode lasers or diode-pumped lasers.

Devices that employ blue laser light have applications in many areas ranging from optoelectronic data storage at high density to medical applications.