初级球差对椭圆偏振涡旋光束深聚焦场的影响

Effect of Primary Spherical Aberration on Tight Focusing of Elliptically Polarized Vortex Beams

研究了椭圆偏振涡旋光束经过具有初级球差的高数值孔径透镜的聚焦特性。基于德拜矢量积分理论,获得了椭圆偏振涡旋贝塞尔-高斯光束经过具有初级球差的高数值孔径透镜后的复振幅的分布函数,根据数值模拟的结果,分析了不同的初级球差系数对右旋椭圆偏振光束和左旋椭圆偏振光束聚焦场光强分布和相位分布的影响。结果表明,随着初级球差系数的增加,椭圆偏振涡旋光束的强度会变小,空心的尺寸会变大;右旋椭圆偏振光纵向分量的相位分布呈现螺旋结构,而且右旋椭圆偏振光和左旋椭圆偏振光的位错线半径会逐渐增大;会聚点逐渐偏离焦平面,纵向光场发生改变。

The focusing properties of elliptically polarized vortex beams through a high numerical-aperture objective with primary spherical aberration are studied.Based on vectorical Debye theory,the complex amplitude distribution of elliptically polarized Bessel-Gaussian beams through a high numerical-aperture objective with primary spherical aberration is derived.Numerical calculation is performed to analyze intensity distribution and phase distribution of the right-handed elliptically（RE） polarized beam and the left-handed elliptically（LE） polarized beam with different primary spherical aberration coefficients.It is shown that the intensity distribution of the vortex beams decreases with the spherical aberration coefficient,but the size of dark core increases.Additionally,the phase distribution of longitudinal component of RE polarized beam presents the spiral structure and the radii of the dislocation lines for RE polarized beam and LE polarized beam increase gradually with the primary spherical aberration coefficient.With the increment of spherical aberration coefficient,the converging point gradually deviates from the focal plane and the longitudinal field changes.