A method of forming annular pump light

In order to get pure annular end-pumping beam to generate Laguerre-Gaussian beams from solid-state lasers, a method with axicon shaping system was put forward. At first, the solid pump light from LD source was collimated by the lens and was coupled into a axicon and a focal lens. And then, the shaping system was obtained and hollow beam with variable size was formed. Based on geometrical optics, theoretical analysis and numerical simulation were made with the aid of the software ZEMAX . The phenomenon of the invariant dark region of annular pump light was also investigated. The results show that power conversion efficiency could reach up to 64.5% by using the system with uncoated axicon.