| 摘要 |
PURPOSE:To contrive secured stability of refractive index and transmittance and reduction in fluorescence, by forming the title element assembly used for laser beams within a specific wavelength region at about <=400nm from a high- purity quartz glass material and specifying the content of OH groups in the structure thereof. CONSTITUTION:An element assembly of a laser optical system used for laser beams within a specific wavelength region at about <=400nm, more limitedly <=350nm is formed from a high-purity quartz glass material and the content of OH groups in the glass material structure is set at >=300ppm. Thereby emission of fluorescence from the laser optical system used for laser beams within a short wavelength region can be reduced to improve stability of refractive index, transmittance, etc. An element assembly extremely suitable as an optical system material for excimer laser can be especially provided. |
