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Applications of a soft X-ray double frequency grating shearing interferometer to laser plasma diagnostics were explored by using a soft X-ray double frequency grating as the shearing interferometric element.To improve the success rate of experiment,this paper analyzed the line parallelism and diffraction efficiency of the double frequency grating.On the basis of the relationship between the line parallelism of the double frequency grating and the interferogram of shearing interferometer,it calculated the technical requirements of line parallelism of the grating.The fabrication method was described,the line parallelism of the grating was realized with the diffraction spot position monitoring,and the moire fringe method was applied in line parallelism judgment for the grating.A double frequency grating with line parallelism less than 0.01° was fabricated.The two groups of diffraction efficiencies of-1 order for the grating were examined in spectral radiation standard and metrology beamline of Hefei National Synchrotron Radiation Laboratory,and the results show both of them are over 10% at 13.9 nm.A shearing interferometer was set up for dense plasma diagnostics,whose results demonstrate that the parallelism and diffraction efficiency of the double-frequency grating can meet the experimental requirements.

To meet the need of 1 m Seya-Namioka monochromator for gratings in the combustion and flame endstation at National Synchrotron Radiation Laboratory(NSRL),1 200 lp /mm Laminar gratings were succesfully fabricated with holographic lithography and ion beam etching.The duty cycle of a resist grating mask was adjusted by resist-ashing,then the resist grating mask was etched in the range of theory design error and its pattern was transfered on a substrate by the scanning ion beam etching method.A gold film with a thickness of 40 nm was coated by ion beam sputtering and an aluminium film with a thickness of 60 nm by evaporating on gratings,respectively,after the rest resist was removed and cleaned.The microstructures of gratings were characterized by an Atomic Force Microscopy(AFM),and results show that the groove depth is 40 nm and duty cycle is 0.45 for the gratings.Synchrotron radiation wavelength scanning were also performed at the exit slit of the combustion and flame endstation,the results indicate that the photon intensity of Al-coated grating is better than that of Au-coated one which agrees well with the calculated results.The Au-coated grating has been used for experimental investigation for 3 years,futhermore its lifetime has been larger than that of the replica grating.

Ion beam etching technologies for developing large aperture Diffractive Optical Elements(DOEs) were reviewed.To meet the requirements of large aperture DOEs in high-power laser systems,an integrated graphite mask for ion beams and a multi-position etching strategy were investigated for a self-established KZ-400 etching facility to improve the uniformity for ion beam etching and the uniformity of ±1% for ion beam current along the major axis of the ion source was achieved in a range of 1430 mm.On-line optical measurement methods and experimental setups for Multilayer Dielectric Gratings(MDGs) and transmission DOEs were presented to measure the 1D spatial distribution of diffraction intensity and the ion beam etching depth based on fringes of equal thickness,respectively,by which the quantitative control of ion beam etching for large size DOEs was completed.Based on above techniques,a series of large aperture DOEs,especially MDGs with diffraction efficiencies more than 95% at 1 064 nm,beam sampling gratings,color separation gratings and beam sampling gratings for synchrotron radiation were fabricated successfully.

To meet the need of soft X-ray self-supported transmission gratings for space detecting and plasma diagnostics,self-supported gold transmission gratings were successfully fabricated with the holographic lithography and plating technology.To obtain photo-resist mask patterns with steep sidewalls,a layer of Anti-reflection Coating(ARC) was used to attenuate standing wave resulting from the substrate with high reflectivity.Then,a plating mask was obtained by coating a protective chrome on the mask and using Reactive Ion Etching(RIE).In this process,the plating mask with desired duty cycle could be fabricated via changing the thickness of the protective coating.Finally,a self-supported transmission grating with a line density of 3 450 gr/mm(290 nm period),a duty cycle of 0.55 and 400 nm thick gold bars was fabricated by plating gold in grooves of plating mask.The grating size is up to 10 mm×15 mm,and its +1 order diffraction efficiency is about 5% in the soft X-ray band between 5 and 12 nm in the National Synchrotron Radiation Laboratory(NSRL).