短语词组短语Beam -waist 压弯的腰multi -beam waist 多光腰optimum beam waist 最佳束腰beam waist radius 光腰半径beam waist spot size 束腰光斑尺寸beam waist location 束腰位置gaussian beam waist 高斯光束束腰minimum beam waist 最小光斑beam waist width 束腰宽度 返回 beam waist