离轴高阶贝塞尔-高斯涡旋光束的传输分析

研究高斯光束经螺旋相位板和轴棱锥产生高阶贝塞尔-高斯涡旋光束的离轴传输情况,对于离轴高阶贝塞尔-高斯光束的成因、 光强分布操控、光斑定位等实际应用具有一定的理论指导意义。利用菲涅尔衍射积分的卷积算法(Triple fast Fourier transform, T-FFT)对离轴高阶贝塞尔-高斯涡旋光束进行仿真分析,着重研究了螺旋相位板和轴棱锥的错位参数、拓扑荷数 以及传输距离等参数对光束带来的影响。分析表明:离轴高阶贝塞尔-高斯光束具有不均匀的光强分布,由于轴棱锥的偏移, 光束会整体发生偏移,传输不同距离光强不均匀分布情况不同,不同的拓扑荷数只影响光斑的扩展,螺旋相位板和轴棱锥离 轴参量值的多种组合会导致多种不同的光强分布情况,甚至出现暗核偏移。

Transmission Analysis of Off-Axis High Order Bessel-Gaussian Vortex Beam

The off-axis transmission of high order Bessel-Gaussian vortex beam produced by spiral phase plate (SPP) and axicon is studied, which can provide reference for the off-axis high order Bessel-Gaussian beams’ formation, intensity distribution control, spot location and other practical applications. On the basis of the theory of diffraction, the transmission of the higher order off-axis Bessel-Gaussian beams is simulated and analyzed by using the triple fast Fourier transform (T-FFT) algorithm. The effects of dislocation parameters, topological charge numbers and transmission distances of SPP and the axicon on the beams are considered during the simulation. The analysis shows that the off-axis higher-order Bessel-Gaussian beams have an uneven light intensity distribution. Due to the shift of the axicon, the beams will be shifted as a whole and the uneven distribution of light intensity at different distances is different. Different topological charge only affects the light spot expansion. Various combinations of the off-axis parametric values for SPP and the axicon will generate different light intensity distributions and even dark core's shifts.