small spot短语⁹⁶⁶⁷⁷⁺⁶ 基本例句 🌏小射灯 As the paraxial approximation is no longer valid for the beams with large divergence angles or small spot size comparable with the wavelength, a rigorous non- paraxial treatment becomes necessary. 当光束具有较大的发散角或光束束腰可与波长相比拟时，傍轴近似不再成立； cnki