Laboratory uses thumb|Violet light from a helium cadmium metal vapor laser. The highly monochromatic color arises from the 441.563 nm transition line of cadmium. Helium–cadmium lasers are a common source of blue or ultraviolet laser light. Lasers at wavelengths of 325, 354 and 442 nm are made using this gain medium; some models can switch between these wavelengths. They are notably used in fluorescence microscopy as well as various laboratory uses requiring laser light at these wavelengths.
Laboratory uses thumb|Violet light from a helium cadmium metal vapor laser. The highly monochromatic color arises from the 441.563 nm transition line of cadmium. Helium–cadmium lasers are a common source of blue or ultraviolet laser light. Lasers at wa?velengths of 325, 354 and 442 nm are made using this gain medium; some models can switch between these wavelengths. They are notably used in fluorescence microscopy as well as various laboratory uses requiring laser light at these waveleng,ths.