关键词: 高光束质量/
高功率稳定性/
谐振腔设计
English Abstract
Design and experimental study on high quality beam and high stability power of laser
An Ran,Fan Xiao-Zhen,
Lu Jian-Xin,
Wen Qiao
1.Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
Fund Project:Project supported by the Special-Funded Program on National Key Scientific Instruments and Equipment Development of China (Grant No. 2012YQ200182), Shenzhen-Hong Kong Innovation Cooperation Project, China (Grant No. SGLH20150205162842428), and Science and Technology Innovation Commission of Shenzhen, China (Grant Nos. JCYJ20170302153540973, JCYJ20170412111625378).Received Date:31 August 2017
Accepted Date:23 January 2018
Published Online:05 April 2018
Abstract:High-performance lasers with high-quality beam laser and high-stability power are widely used for laser machining, laser precision measuring, etc. Reflection curved mirrors are widely used in lasers to provide several small intracavity focal spots and reduce the dispersion and volume of the laser. The primary disadvantage of using reflection curved mirrors in folded resonators is that relatively large angles of incidence deform the circular transverse pattern of the output beam and limit laser performance. In addition, in high power lasers or ultra short pulse lasers, the gain medium thermal lens focal length fluctuation is the primary cause of the instability of laser output power. This paper focuses on beam quality and power stability of laser, and an effective method of solving the two problems, i.e., astigmatism and instability power of laser, is presented. The laser resonator with high-quality laser beam and high-stability power is very easy and intuitive to design by this method, in which the resonator transform circle graphic theory is used and the thermal lens and astigmatism compensation is taken into account. The theoretical investigation shows that the astigmatism in two terminal arms of the folded laser resonator can be successfully eliminated by using this method, and the experimental measurements of the pattern of the laser output beam show that the deformations of spot intensity profiles in the two terminal arms can be simultaneously compensated for completely in the cavity, which is in good agreement with the analytical prediction. When the focal length of the laser crystal thermal lens varies, the variations of radii of spots not only at some key position, but also at all locations of the laser resonance designed by this method, are overtly smaller than the variation of the normal resonant cavity. The stability of the output laser power of the laser is better than that of a universal laser resonator under the same external conditions.
Keywords: high beam quality/
high stability power/
resonator design
