Toric concave mirror laser resonator with a big Fresnel number

摘要

A new type of toric concave mirror laser resonator with a big Fresnel number is presented. The M~(2) factor of an output laser beam of the new resonator with a Fresnel number of 8.05 is close to that of the plane-concave stable resonator with a Fresnel number of 2.01, the volume of output mode of the new resonator is about four times of that of the plane-concave stable resonator. A 3.2 kW doughnutlike laser beam with an M~(2) factor of 1.9 is obtained experimentally by using the new resonator on a high-power transverse flow CO_(2) laser, while the similar laser power with an M~(2) factor of 7.5 is obtained by using a plane-concave stable resonator with the same Fresnel number. Results show that a toric concave mirror laser resonator can permit operation of the laser with high power and high beam quality mode in the laser with large gain volume.