Bessel光束经椭圆环形孔径后的衍射光场

Diffraction optical field of the Bessel beam through elliptical annular aperture

基于菲涅耳衍射积分理论及硬边孔径的复高斯函数展开法导出了Bessel光束经椭圆环形孔径后的光场表达式,数值模拟了其光场的强度分布.研究了Bessel光束经椭圆环形孔径后的光场变化及其传播过程;在实验上利用轴棱锥输出的近似无衍射Bessel光,通过椭圆环形孔径,使用电荷耦合器件拍摄得到不同传播距离处的光强分布.理论结果和实验结果均表明无衍射光束经椭圆环形孔径后会产生空心光束.

Based on Fresnel diffraction theory and complex ~ausslan mnctlon expansion oI naraoe^ect aperture, ~ up^L~,~l field formula of Bessel beam propagating through an elliptical annular aperture is derived, and the transverse intensity distribution of the beam is numerically simulated. The changes of the optical field and the propagation process of the diffracted beam behind the elliptical annular aperture are studied. In the experiment for the first time, a quasi non- diffracting beam is generated by an axicon and the patterns that are due to the beam diffraction by an elliptical annular aperture at different propagation distances are observed with a charge-coupled device camera. The theoretical analysis and experiuxentat results both show that Bessel beam passing through an elliptical annular aperture can generate a hollow beam.