XeF XeCl XeBr KrF KrCl 193 nm 351 nm 308 nm 282 nm 248 nm 223 nm Excimer Lasers 19 ArF 176 nm Xe 2 157 nm Excimer Gas Media and Emission Wavelengths F 2 126 nm Ar 2 116 nm Table 2.1 H 2 18