中文摘要：

本文通过对BaAlBO3F2（BABF）晶体进行掺杂以增加晶体的双折射率，从而使BABF晶体的最短直接倍频波长紫移，拓宽其应用波段。研究发现Ga掺杂能够使BABF晶体的最短直接倍频波长从273nm紫移至259．5nm，理论上能够实现四倍频（266nm）激光输出。采用优化的B2O3-LiF-NaF助熔剂体系，通过中部籽晶法生长出尺寸为25mm×20mm×10mm的Ba（Al，Ga）BO3F2晶体。对该晶体的透过光谱、光学均匀性、弱吸收、倍频匹配曲线、粉末倍频效应和激光损伤阈值的性能进行了表征，结果显示了该晶体在紫外波段激光输出的潜能。

英文摘要：

The BABF crystals were doped to amplify its birefringence, thus to blue shift its shortest SHG wavelength and to broaden its application waveband. It＇s found that Ga doping blued shift the shortest SHG wavelength of BABF crystal from 273 nm to 259.5 nm, making fourth harmonic generation laser output （266 nm） of BABF crystal theoretically possible. Single crystal of Ba （ Al, Ga） BO3 F2 with the dimension of 25 mm × 20 mm × 10 mm was grown by middle-seeded solution growth technology and optimized B203-LiF-NaF flux system. The transmission spectrum, optical uniformity, low absorption, SHG matching curve, second-harmonic intensity and laser damage threshold of the Ba（ Al, Ga）BO3F2 crystal were investigated, and the results showed that the crystal was potential in laser output of ultraviolet waveband.