摘要
本文在光学主轴坐标系下,对双轴晶体LiB_3O_5共线和频与倍频特性进行了计算与分析.给出了xy面应用tyyeⅠ相位匹配及yz面应用typeⅡ相位匹配情况下,基波波长与相位匹配角、有效非线性系数、离散角、容承角及基波频谱带宽的关系曲线,对LiB_3O_5晶体的实验与应用提供了有指导意义的理论结果.
According to Sellmeier equation, the calculation and analysis on the collinear sum-frequence generation and frequency doubling in biaxial crystal LiB3O5(LBO) are made in terms of principle axes. The results demonstrate that sum-frequency mixing of a Nd:YAG laser<1.064nm)and a dry laser (from 0.56μm to 0.85μm) radiation can be realized in both of the two types of phase-matching(PM)process. Type Ⅱ PM is generally more efficient than that of type Ⅰ, while type 11111111 is phase matchable over a larger wavelength range. As mentioned in the latter, 0.266μm UV radiation can be generated by sum-frequency mixing of the Nd:YAG laser with 1.064μm radiation and its third-harmonic generation with 0.355μm radiation by type I PM process in LBO crystal.An interesting feature of sum-frequency generation and frequency doubling in LBO is that non-critical phase matching(NCPM)can be obtained in x-y plane (type Ⅰ PM)and in y-z plane (type Ⅱ PM) at room temperature, while the nonlinear coefficient deff reaches its maximum. NCPM ensures the advantage of both a large acceptance angle and a small walkoff angle, thus makes LBO with a longer coherent length and higher efficiency in frequency conversion. The curves of the phase matching angle,effective nonlinear coefficient,walkoff angle, acceptance angle and spectral bandwidth versus the fundamental wavelength are plotted according to the formulas we derived in type I PM in x-y plane and type Ⅱ PM in y-z plane, respectively. The theoretical guiding to experiments and applications in LBO is presented.
出处
《发光学报》
EI
CAS
CSCD
北大核心
1991年第2期89-97,共9页
Chinese Journal of Luminescence
