Aug 29 2013
Helium selenium lasers are a type of metal-vapour laser. The operation mode of this laser is similar to that of the helium cadmium laser. Spontaneous emission occurs when selenium switches between its excited states. As many as 24 different wavelengths of radiation are emitted by this laser. The wavelengths lie between the red and the UV region of the spectrum.
Construction wise, the helium selenium laser is similar to the helium mercury laser, except that it has a narrower laser tube. The gas discharge tube (containing helium) houses a heating element that heat the selenium pellets and controls the selenium vapour pressure. The lasing medium consists of helium and selenium vapour. The laser tube is made of Pyrex glass and hemispherical configuration of mirrors is used. The power supply is electric discharge. This laser emits lights as many as 24 wavelengths of light that lie between the red and the UV region.
Caution needs to be exercised while handling the power supply, laser output and disposing selenium (toxic by nature). It is not used in material processing as a number of cheaper substitutes are available.
||24 wavelengths between red and UV regions
The applications of the helium selenium laser are limited. This laser mainly used for scientific research.