Taking account of the transmission characteristics of the diaphragm and the saturation of the gain in the process of light amplifying,the evolution of the beam inside the Cassegrain multi-pass amplifier is numerically simulated by using the ray-tracing and split-step fast Fourier-Bessel transform(SSFFT) methods,the annular beam is coming from Q-switched Nd∶glass laser with ring cavity.

For the description of the focusing properties of a Bessel beam generated by an axicon, we first deduce a type of analytic expression other than Huygens-Fresnel diffraction integral theory.

In the teaching of physical experiment of uncertainty theory, assessing the experiment data of convex mirror focus measurement with Bessel method, meets with some application problems.

The Zeroth-order Bessel Function and Nondiffraction Beams;

The Solution of Bessel Function About Circular Plates with Three Generalized Displacements on the Elastic Foundation;

An error analysis of numerical calculation by series formula of Bessel function;