OPTICAL PARTS FOR SHORT WAVELENGTH LASER

摘要

PURPOSE:To permit constitution of a folding type excimer laser oscillator having a high beam utilization rate by forming a reflection optical element and partially transparent optical element so as to bisect one main lane of a transparent substrate having the extremely precise optical main plane. CONSTITUTION:UV light is projected by a preliminary ionization means to the folding type excimer laser to ionize a gain medium 5 between main electrodes 8 and 8' of said laser prior to impression of high-voltage pulses to the electrodes 8, 8'. The gain medium 5 is excited when a glow discharge is generated between the electrodes 8 and 8'. Laser oscillation is then executed by an optical resonator consisting of the total reflection optical element 41 and optical element 51 provided on one main plane of the transparent body 1. The laser light emits from the resonator by passing the partially transparent element 41. The total reflection optical element 31 is constituted by a alternately evaporating low refractive index- and high refractive index materials to the regions of half the surface of the transparent substrate 1 finished to an extremely precise specular surface in such a manner that the respective optical film thicknesses attain lambda/4 thereby forming the multi-layered films having >=95% reflectivity on the surface of integral type optical parts. The partially transparent element 41 having 0-70% reflectivity is formed in the remaining region.