Helium mercury laser falls into the category of metal-vapour lasers. It is similar in operation to the helium-neon or the Argon/Krypton lasers. It is also known as the ‘mercury vapour ion laser’ due to its operating principle based on the ionic transitions of mercury. It is capable of generating wavelengths lying in the visible region of the electromagnetic spectrum.
Construction, alignment and operation of this laser are simple to carry out, with minimum components required and simple mirror arrangements. The lasing medium is low pressure helium and mercury vapour. The laser tube is made of Pyrex glass and dielectric concave mirrors are used. The power supply is electric discharge. This laser emits lights of wavelengths 567 and 615 nm.
The safety aspects of the laser operation revolve around the laser output, electric discharge and the chemicals. The laser output must not be viewed without safety goggles. Care must be taken while handling the power supplies. Mercury is a toxic metal; hence it must be disposed with care.
The applications of the helium mercury laser are limited. This laser mainly used for scientific research.