The zigzag grating is one of the newly proposed optical dispersive elements which has an excellent diffraction characteristics and has important applications in the spectrum measurement and analysis. The simulation results of the diffraction pattern of the zigzag grating for X ray are presented using a new numerical method based on the convolution theorem, and comparison of its diffraction pattern with those of the traditional grating and sinusoidal grating are studied. It is seen from the results that all higher order diffractions of the zigzag grating are suppressed below the level of four orders of magnitude compared with the first order diffraction, which is superior to the traditional grating, being consistent with the theoretical expectations. Moreover, the impact caused by the absorber is analyzed, which eventually confirms that the zigzag grating has perfect practical application feasibility. The conclusions provide a potential alternative for the physical design of the zigzag gating, which is expected to replace the traditional transmission grating in applications to the soft X-ray spectrum measurement.

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In single-shot, ultrafast time-resolved measurements, the combination of linear chirp pulse and spectrometer is a common way. In this paper, according to the time-frequency mapping relationship of linear chirp pulse and utilizing an imaging spectrometer as a recording system, we design a chirped pulse velocity interferometer for the ultrafast measurement of free surface velocity. Theoretical research on the principle and applicability shows that picosecond resolution is achievable and the velocity sensitivity is easily adjustable, which greatly widens applications of the velocity interferometer. The numerical simulation of the measurement process shows that reconstructed velocity signal is well consistent with the given velocity, further confirming the feasibility of the chirped pulse velocity interferometer.