title: Toric concave mirror laser resonator with a big Fresnel number.
abstract: A new type of toric concave mirror laser resonator with a big Fresnel number is presented. The M2 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 doughnut-like laser beam with an M2 factor of 1.9 is obtained experimentally by using the new resonator on a high-power transverse flow CO2 laser, while the similar laser power with an M2 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.
authors.affiliation: Wuhan National Laboratory for Optoelectronics, National Engineering Research Center for Laser Processing, School of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Hubei, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Yingxiong
authors.forename: Tang
authors.initials: T
authors.lastname: Xiahui
authors.forename: Xiao
authors.initials: X
authors.lastname: Yu
authors.forename: Liu
authors.initials: L
authors.lastname: Juan
authors.forename: Wang
authors.initials: W
authors.lastname: Du
authors.forename: Peng
authors.initials: P
authors.lastname: Hao
authors.forename: Deng
authors.initials: D
authors.lastname: Qiansong
authors.forename: Zhu
authors.initials: Z
authors.lastname: Xiao
authors.forename: Li
authors.initials: L
authors.lastname: Zhengjia