HIGH-PRECISION MINUTE RING BEAM LIGHT SOURCE AND HIGH- PRECISION MINUTE RING BEAM CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide a high-precision minute ring beam light source and a high-precision minute ring beam control method which generate a beautiful ring beam which can be used for an optical pincette, an energy supply light source for micromachining, or the like. SOLUTION: A coupling lens 1 is so arranged that its optical axis A1 is inclined to a convergence point C of an incidence end face 30 of a fiber 3 as a columnar optical element, and the fiber 3 and an exit lens 4 are coaxially arranged. The coupling lens 1 makes the luminous flux from a light source 2 incident on the convergence point C of the fiber 3 at prescribed convergence angleαand incidence angleβ. The lens 4 is arranged a length equal to the focal length of the lens 3 apart from an exit end face 31 of the fiber 3 and converts a ring beam into a parallel ring beam or a converging ring beam. As the result, a high-precision minute ring beam light source whose light intensity distribution in the diametral direction is not Gaussian but is doughnut is obtained.