多色高斯光束照射下透镜轴棱锥的聚焦特性

Focused Characteristics of a Lens Axicon Illuminated by Polychromatic Gaussian Beams

从菲涅耳衍射积分公式出发,推导多色高斯光束被球差透镜衍射后光强分布的解析公式,进行数值模拟和物理分析.结果表明,光谱半宽σ小的多色高斯光束照射透镜轴棱锥时,不同观察面的光强分布均为J20的形式.随观察平面远离透镜轴棱锥,横向光强第1零点半径逐渐增大;但当σ取值较大时,横向光强分布不再是J20的形式,且横向光强的零点不再明显.对于轴上光强而言,多色高斯光束提高轴上光强分布的均匀性.

Staring from Fresnel diffraction integral, we deduced the optical intensity distribution in the Fresnel zone of the diffraction field of the annular-aperture lens axicon. A numerical calculation and physical analysis is performed to investigate the intensity distribution of the diffraction field. It is shown that when is small the pattern of the transverse intensity of different observing plane can be described by like pattern. While the observing plane is far away from lens axicon the radius of first zero order of the transverse intensity increases. However, with the increment of the minimum transverse intensity do not equal to zero any more. For axial intensity, polychromatic Gaussian beam resulted in significant improvement in the uniformity of the distribution of the axial intensity in comparison with the monochromatic Gaussian beam.