设计了对称贝塞尔(Bessel)谐振腔,它由两个完全相同的锥透镜构成,两锥透镜锥顶相对。底面镀膜对激光波长全反。利用光线追迹法对光线通过锥透镜和双锥透镜谐振腔的等效波导系统进行了分析。利用Fresnel—Kirchhoff衍射积分定律和Fox—Li迭代法,通过数值计算得出了谐振腔的稳定场分布。几何光学和波动光学两种分析方法均表明对称腔内产生振荡的激光是Bessel光束。这种对称谐振腔能够直接输出无衍射Bessel光束,并且构成谐振腔的锥透镜结构简单、光损伤阈值高.为主动式产生无衍射光提供了新的方法,具有广阔的应用前景。
Symmetric Bessel resonator was designed which consisted two identical axicons, their bottom surface were coated with total reflective film for laser wavelength and cone vertexes were opposited. Propagation of light rays through an axicon and the equivalent waveguide system of double-axicons resonator was analyzed by using ray tracing method. Optical field distribution in the resonator was calculated by using Fresnel-Kirchhoff diffraction integral and Fox-Li iterative method. Both the analytical methods of geometrical optics and wave optics demonstrate that the symmetric resonator generates Bessel beam. This symmetric resonator can output non-diffracting Bessel beam directly, and axicon has a simple structure and high optical damage threshold. This new way for generating non-diffracting beam by active method shows wide application prospect.