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This work aims to design and fabricate sub-wavelength structures on lithium triborate surface for increasing its transmittance at 1064 nm. The finite-difference time-domain (FDTD) method is used to discuss the effects of subwavelength structure parameters such as period, depth, duty cycle and shape factor on the reflectivity. The subwavelength surface microstructures are fabricated by interference lithography technique and reactive ion beam etching method. The transmittance of the lithium triborate with single-side sub-wavelength structures is measured by UVvisible- near-infrared spectrophotometer. The results show that the transmittance of the sample with single-side microstructures at 1064 nm is about 4% higher than that of the polished substrate.

In a previous study, the temperature-rise of a spectral beam combining grating was analyzed theoretically and experimentally. It was concluded that the temperature of a grating can be effectively reduced by increasing the substrate thickness or by using a substrate material with higher thermal conductivity. In this study, yttrium aluminum garnet (YAG) was used as the substrate material to fabricate a spectral beam combining grating. The temperature, distortion, and far-field beam quality of the YAG-substrate-grating were analyzed theoretically and experimentally. It is concluded that, compared with the traditional quartz-substrate-grating, not only can the YAG-substrate-MDG withstand higher power, but the beam quality of the diffraction laser is also better.

In this work, a chirped volume Bragg grating (CVBG) with over 40 nm high efficiency broadband spectra for pulse compression of near 100 fs was studied. Based on the fundamental matrix method, the effects of various structural parameters of CVBG on its diffraction characteristics were analyzed and then a design of broadband and high efficiency CVBG was proposed. Afterward, the monolithic CVBG was utilized to stretch and recompress a 100 fs pulse with a center wavelength of 1030 nm. The result shows this device has a high diffraction efficiency (84%) and a fine reciprocity. For the fabrication of large-size broadband CVBGs, double cylindrical wave holographic interference in photo-thermorefractive (PTR) glass was applied to achieve a wide range uniform and stable light field, which could greatly minimize unnecessary space chirp.

In this paper, metallic pulse compression gratings (MPCG) with three kinds of grating structures are manufactured. The diffraction efficiency and bandwidth of samples are measured and it can be found that the different grating structure has different diffraction efficiency and bandwidth. Laser damage tests of samples are implemented by an 800±30 nm laser at pulse duration of 31 fs and it can be also found that the different grating structure has different laser-induced damage threshold. Experimental measurements illustrate that the grating structure has a great influence on bandwidth, diffraction efficiency and damage threshold. The typical damage morphologies of MPCG reveal that the damage is induced by absorption and thermal stress.