| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a synthetic quartz glass optical member in which decrease in transmittance when irradiated with deep ultraviolet rays is suppressed, increase in an absolute refractive index, variations in a refractive index distribution and generation of fluorescence are prevented, and generation of MC (microchannels) when output of an excimer laser in a deep ultraviolet ray region is enhanced is suppressed.SOLUTION: The synthetic quartz glass optical member is used for deep ultraviolet rays at a wavelength of 250 nm or shorter; and the synthetic quartz glass member has two major surfaces and has the following characteristics. A difference (average H(main part)-average H(surface proximity region)) between an average hydrogen molecule concentration in a surface proximity region within 1 mm depth from one of the major surfaces and an average hydrogen molecule concentration in a main part of the synthetic quartz glass member excluding the surface proximity region is larger than a variation of the hydrogen molecule concentrationΔH(main part) in the main part of the synthetic quartz glass member; the average hydrogen molecule concentration in the main part of the synthetic quartz glass member is 3×10to 5×10molecules/cm; and the average hydrogen molecule concentration in the surface proximity region is less than 3×10molecules/cm.</p> |
