离散角 meaning in English

walk off angle
walk-off angle

Effects of the walk - off angle on the coefficients of reflection and transmission
离散角对反射与透射系数的影响
But the large wall - off angle ( about 3 . 70 ) and small acceptance angle ( about 0 . 35 mrad ) are the problems in the process of frequency doubling
但基于离散角大(约为3 . 711 ) 、接受角度又小(约0 . 35mrad ) ，所以会给倍频过程调节带来了一定的难度。