Previous research on achieving the alignment of compression gratings has mainly focused on the parallelism of the gratings. We propose a promising method to achieve parallelism and especially accurately adjust the grating to its optimum working angle to achieve dispersion compensation. A spectrometer and a precisely adjustable mirror pair are cooperatively used to measure the wavelength of the light diffracted by the grating, satisfying the Littrow condition. Meanwhile, the tiny slit of the spectrometer can decrease the grating-tip and in-plane rotation error during the alignment procedure. Using this technique, the residual phase of the compressed pulse is optimized and the compressed pulse duration is 25.4 fs, which is 1.06 times that of the Fourier-transform-limited compressed pulse.
Meter-sized gratings are urgently required by ultra-short ultra-high lasers, especially petawatt and multi-petawatt
lasers, in the world wide. Object-image-grating self-tiling method gives a way to achieve an ideal grating tiling
condition by completely eliminating three tiling errors within a traditional tiled grating. However, some
application problems challenges it actual application in laser systems. In this paper, we will discuss the influence
of two important problems: the stability problem and the spectrum amplitude modulation problem. And related
simulations and analyses are developed to promote the application of this method in large-scaled lasers systems.
Fine control of Optical Thin Film Stress is critical to develop an expected profile parameters of large aperture
coated optics. In our latest effort, the evolution of stress and force per unit width of multilayer thin film formulas,
(H2L)<sup>6</sup>, (H2L)<sup>5</sup>H and (HL)<sup>7</sup>, consisted of HfO<sub>2</sub> and SiO<sub>2</sub> were researched. The stresses of SiO<sub>2</sub> single layers deposited on
the HfO<sub>2</sub> were small than those grew on glass and get smaller as the multilayer thin film deposited. While the stresses of
HfO<sub>2</sub> films deposited on the SiO<sub>2</sub> were positive correlation with the stress of SiO<sub>2</sub>.
Spectral clipping effect in a chirped pulse amplification laser system is developed in this paper. A grating-size-limited
stretcher/compressor as well as an amplifier can alter the spectrum profile of an ultrashort pulse, so the temporal profile
will be influenced. We present a model of spectral clipping effect and calculate the wavelength-dependent spectral
clipping ratios in a CPA laser system for a variety of matched stretcher-compressor designs. Then we analyze the output
pulse's temporal distribution, and find that the temporal contrast ratio is mainly determined by the stretcher and the
amplifier. The pulse duration of the output pulse is mainly influenced by the amplifier.