HeCdlaserit

HeCdlaserit, also known as the Helium-Cadmium laser, is a gas laser that emits light in the blue and ultraviolet regions of the electromagnetic spectrum. It operates by exciting a mixture of helium and cadmium vapor. The primary laser lines are at 441.6 nm (blue) and 325.0 nm (ultraviolet). These wavelengths make it useful for a variety of scientific and industrial applications.

The construction of a HeCd laser typically involves a sealed tube containing helium gas and a small amount of cadmium metal. When an electrical discharge passes through the gas mixture, helium atoms are excited and collide with cadmium atoms, transferring energy and causing the cadmium atoms to reach an excited state. As these excited cadmium atoms return to a lower energy level, they emit photons at specific wavelengths. The laser cavity, formed by mirrors at either end of the tube, amplifies this light through stimulated emission, producing a coherent beam.

HeCd lasers are known for their relatively high power output in the blue and UV ranges compared to other gas lasers. However, they also have a shorter lifespan due to the gradual depletion of the cadmium vapor and the degradation of the electrodes. Despite these limitations, their unique spectral output has led to their use in applications such as fluorescence microscopy, holography, spectroscopy, and certain photolithography processes. Research into improving their efficiency and lifespan continues.