| 摘要 |
<p>An excimer laser having reduced bandwidth variation is provided. The laser has an assembly of components comprising a beam expander (120) having at least two prisms (122, 124 and 126) that reduces the spectral bandwidth of the laser beam that is passed through the assembly. At least one of the prisms (122, 124 and 126) of the beam expander (120) is made of a thermally stable material, wherein the material has a coefficient/CM of absorption of no more than about 0.1 percent for light having the desired wavelength, a rate of change of refractive index with temperature of no more than about 2.3 x 10-6 °C a thermal conductivity of at least about 9,71 W/m- °C at 20 deg C, and or a coefficient of thermal expansio n of at least about 9 x 10-6 (deg C)-1. In a preferred embodiment, the stability of beam profile is improved, the variation in spectral banwidth of the beam from the laser is reduced, the spectral bandwidth itself is also reduced, and the laser exhibits greater voltage stability.</p> |
