中国物理B ›› 2009, Vol. 18 ›› Issue (3): 1089-1095.doi: 10.1088/1674-1056/18/3/042
饶长辉1, 姜文汉1, 宁禹2, 余浩2, 周虹3
Ning Yu(宁禹)a)b)†, Zhou Hong(周虹)b)c), Yu Hao(余浩)a)b), Rao Chang-Hui(饶长辉)b), and Jiang Wen-Han(姜文汉)b)
摘要: One of the important characteristic of adaptive mirrors is the thermal stability of surface flatness. In this paper, the thermal stability from 13℃ to 25℃ of a 20-actuator bimorph deformable mirror is tested by a Shack--Hartmann wavefront sensor. Experimental results show that, the surface P--V of bimorph increases nearly linearly with ambient temperature. The ratio is 0.11μm/℃ and the major component of surface displacement is defocused, compared with which, astigmatism, coma and spherical aberration contribute very small. Besides, a finite element model is built up to analyse the influence of thickness, thermal expansion coefficient and Young's modulus of materials on thermal stability. Calculated results show that bimorph has the best thermal stability when the materials have the same thermal expansion coefficient. And when the thickness ratio of glass to PZT is 3 and Young's modulus ratio is approximately 0.4, the surface instability behaviour of the bimorph manifests itself most severely.
中图分类号: (Lenses, prisms and mirrors)