光场的非傍轴性对光谱移动和光谱开关的影响

Effect of nonparaxiality of optical field on spectral shift and spectral switching

利用瑞利衍射积分公式,推导出多色高斯光束被硬边光阑衍射后光谱的解析公式,傍轴近似的光谱公式可作为特例得到.着重研究了束腰宽度与中心波长之比w0/λ0和截断参数δ对光谱移动和光谱开关的影响.结果表明,只有当w0/λ0和δ满足一定条件时,傍轴近似结果才与非傍轴结果一致.光场的非傍轴性会引起光谱移动不同和产生光谱开关的临界位置变化.

Based on the Rayleigh diffraction integral, an analytical expression for the spectrum of polychromatic Gaussian beams diffracted at an aperture is derived,and the paraxial results are treated as a special case of our general expression.The mainattention is focused on the effect of ratio of the waist width to the central wavelength ω0/λ0 and truncation parameter δ on spectral shift and spectral switching.Only when ω0/λ0 and δ satisfy certain conditions are the paraxial approximation results consistent with the nonparaxial ones.The nonparaxiality of field results in different spectral shifts and changes of the critical position where the spectral switching takes place.