Therefore, an improved search strategy of text searcher is proposed in this paper, which filters the search tree based on the judge theorem of logical mismatching attributes, and reduces the scope of search tree, and improves the search efficiency of match candidates.

A difforent frequency generation of nonlinear optical crystals of AgGaSe_2 and AgGaS_2 has been analyzed based on the three-wave coupled equation and energy consesrvation in the phase-matching of type-Ⅰand type-Ⅱ.

Based on the calculation and discussion on the phase-matching,walk-off angle,acceptance angle and effective nonlinear coefficient for the KTP crystal,and on the numerical simulations of the angle-tuning curve and gain curve,the tuning spectrum and cutting angle of the KTP was finally established as 1.

Energy conversion process and spatial distribution of forward-propagating signal wave and backward-propagating wave of sum frequency under phase-matching condition were investigated.