The soft X-ray and extremely ultraviolet filters with negligible pinholes transmittance

It is proposed to fabricate two-layer thin film filters without pinholes transmittance of visible and UV light. We describe the design and performance of these filters. Filter consists of two layers of thin metal films fixed to each side of porous membrane with thorough pores or transmission diffraction grating as support. As examples it was made Al or Rh two-layer thin film filters on metallized porous track membrane supports with the 10−9–10−10 level of visible and UV light rejection at transmittance T∼0.1 ÷ 0.01 in the Extreme ultraviolet region. Proposed filter is appropriate in the optical experiments with strong continuous X-ray and Extreme ultraviolet radiation sources such as laser plasma, SR sources and the Sun.