Development of focusing supermirors by means of ion beam sputtering and ultra-precise figuring techniques

Yamazaki, Dai; Maruyama, Ryuji; Kasugai, Yoshimi; Harada, Masahide; Soyama, Kazuhiko; Hayashida, Hirotoshi*; Nagano, Mikinori*; Tabata, Takaaki*; Mitsushima, Naoki*; Yamamura, Kazuya*

no journal, , 

We have been developing focusing supermirrors by depositing a supermirror on a precisely figured aspheric surface. Surface of a quartz substrate is figured using the "numerically-controlled local wet etching" technique. The figured surface shows a figure error of less than 1 micrometer p-v and an RMS roughness of less than 0.2 nm. Deposition of NiC/Ti supermirror (m=4) with ion beam sputtering keeps the figure error within several micrometers p-v and the roughness almost unchanged. A one-dimensional elliptical supermirror of 400mm in length was developed and it successfully achieved focused peak width (FWHM) of 0.128 mm and peak intensity 52 times that of unfocused (divergent) beam. We also tried two-dimensional focusing using two (vertical and lateral) focusing mirrors in a Kirkpatric-Baez configuration and successfully focused the beam to a spot of 0.5 mm in diameter.