 In 1962 , a group of researchers at Bell Laboratories discovered laser action in xenon , and later found that the laser gain was improved by adding helium to the <unk> medium . The first excimer laser used a xenon dimer ( <unk> ) <unk> by a beam of electrons to produce stimulated emission at an ultraviolet wavelength of 176 nm . Xenon chloride and xenon fluoride have also been used in excimer ( or , more accurately , <unk> ) lasers . The xenon chloride excimer laser has been employed , for example , in certain <unk> uses . 
