Characteristics and geometry optimization of a hollow cone for guiding and focusing laser light

Abstract

A highly focused beam with spot radius of around 1 m and enhanced light intensity is obtained by using an open hollow cone. Two-dimensional and three-dimensional finite-difference time-domain simulations are performed for clarifying light propagation characteristics and the cone geometry dependence of the cone-focused laser light. Two important parameters characterizing the cone-focusing effect are introduced, which are opening angle and cone tip size. By changing these parameters, the laser intensification, field spatial distribution at the cone tip and the near-field transmission can be controlled. Understanding this is quite important in designing the optimum cone shape for fast ignition and determining the basis for using hollow cone targets as devices for generating high energy charged particles. laser beam focusing, hollow cone, finite-difference time-domain (FDTD) method PACS number(s): 41.85.Lc, 42.79.Gn, 42.25.Bs Citation:Zeng X H, Fan D Y. Characteristics and geometry optimization of a hollow cone for guiding and focusing laser light.