超声光衍射强度的一组解析表达式

对光垂直入射于声波传播方向,而在声-光衍射谱中只有零级和正、负一级光的特定条件下,本文应用简正波方法推导了该三级衍射光（n=0,n=+1和n=-1）强度的解析表达式。该表达式与Nath从Raman-Nath方程出发所给出的结果是一致的。文中,应用数值计算方法,在1≤Q≤10的范围内,给出了该表达式能成立的条件。

A GROUP OF ANALYTICAL EXPRESSIONS OF THE LIGHT INTENSITIES DIFFRACTED BY ULTRASONIC WAVES

The analytical expressions for the intensities of the light diffracted by ultrasonic waves are derived by means of the normal mode approach under such a limited situation that the incident light is normal to the acoustic waves and only three orders （n=0, n=+1 and n= -1） appear in the aeousto-optical diffraction spectrum. The results are coincident with that given by Nath based on the Ramen-Nath equations. A criterion for the validity of those expressions is obtained by using numerical calculations implemented in the range of 1 ≤ Q ≤10,and it is demonstrated that the expressions will be valid as long as the condition of s=w/Q≤0.3 maintains.