Multilayer coated grazing incidence condenser for large numerical aperture objective at wavelength of 45  nm

Abstract

A grazing incidence condenser is developed for objectives with large numerical aperture working in Carbon-window wavelength region (λ=4.4-5.0 nm) with the use of a point light source. The condenser is composed of four pieces of toroidal mirrors and a piece of the mirror was fabricated to evaluate the performance of the mirror. The radii of the toroidal mirror are determined by ray-trace calculation, and each radius of the mirror substrate and the roughness of the polished surface were evaluated to satisfy the designed parameter. A Co/C reflection multilayer is also designed to reflect soft x-ray light at 4.5 nm wavelength, and the reflection multilayer was deposited on the mirror surface. Measured reflectance of the toroidal mirror with the reflection multilayer is higher than 0.32 at 4.5 nm wavelength.

Development of laboratory-type soft X-ray microscope, CXRM, in Water-window using LPP light source

“…The SX light is collected by the condenser optics which is composed of two toroidal mirrors. The design of the toroidal mirror is reported elsewhere [3]. The mirror surface is coated with a Sc/Cr/Mo reflection multilayer designed to reflect the Bi emission [2,4].…”