VUV and soft x-ray diffraction gratings fabrication by holographic ion beam etching

Holographic and ion beam etching technique has become routine means for fabricating vacuum ultraviolet and soft x-ray diffraction gratings. A novel technique has been successfully, in which oxygen reactive ions etching was used to achieve resist ashing of the grating, to fabricate diffraction gratings with holographic ion beam etching. The new technique was used to fabricate a spherical blazed grating, 1200g/mm and 130 nm blazed wavelength, and some laminar gratings for monochromators in the beamline of National Synchrotron Radiation Laboratory. The results show that the new technique can considerably lower the stringent requirements of holographic exposure and development, and makes it controllable to make smooth grooves with desirable depth and duty cycle. A gold transmission grating is one of the critical elements in the soft x-ray spectrometer for plasma diagnostics. With holographic-ion beam etching technique, a number of self-supporting transmission gratings have been fabricated for inertial confinement fusion (ICF) diagnosis.