The helium cadmium (HeCd) laser is a gas laser, similar in operation to a helium neon laser. The lasing element, cadmium, is heated to convert it into the gas phase. Collisions with He atoms which have been exicted by electrical discharge then excite the Cd atoms into the laser emitting excited state.
Working with He-Cd lasers involves a number of hazards beyond the laser light itself. The laser tube becomes hot during use, which may cause burns on contact with skin. In addition, the laser tube should be carefully handled to avoid exposure of toxic cadmium to the environment.
The transitions in He-Cd laser are between the energy levels of singly ionized Cd atoms. He-Cd lasers are widely used in the optics laboratory, for example for holographic gratings.
He-Cd laser is extensively used for the following applications:
- 3-D stereolithography applications
- Embossed holography
- CD mastering
- Diffraction grating fabrication
- Nondestructive testing