Functional measurement smart lab
Assistant Professor HATANO Tadashi
Development of soft X-ray multilayer optics
- multilayer mirror,multilayer-coated diffraction grating,multilayer polarizer
- Research Activities
Development of normal-incidence high-reflectance imaging mirrors and small-angle-of-incidence high-diffraction-efficiency gratings coated with multilayer reflectorsLenses and mirrors which are used in visible light region are not applicable to electromagnetic wave in the energy region from vacuum ultraviolet to soft X-rays due to their high absorption coefficients and low reflectances. The highly absorptive property inhibits realization of transmission elements except for the special cases. On the other hand, there exist practically used mirrors against the low reflective property, such as grazing incidence mirrors in the total reflection regime and multilayer mirrors using constructive interference. Multilayer mirrors enable high throughput optics with low aberration and high numerical aperture and improve performance of imaging mirrors and diffraction gratings. This study is aimed to develop multilayer optics over ultraviolet and soft X-rays by stacking several to several hundred layer thin films with thickness control in the nm precision using ion beam sputtering deposition method. These multilayer optics have been developed; Mg/Si multilayer mirrors for He discharge sources, Al/YB6 multilayer polarizers for magnetic rotation spectroscopy around M-edges of transition metals, Mo/Si multilayer mirrors for EUV microscopes, Ni/La/C-coated diffraction gratings for B K-emission spectroscopy, Sc/Cr/Mo multilayer mirrors for the water window microscopes, W/C multilayer diffraction gratings for L-emission spectroscopy of transition metals and so on.