Diskspring was used in new type of laser optical mounts for reposition. Due to stress relaxation of diskspring after long period loading, the laser optical mount’s adjusting platform would have titling drift. When a mirror mounted on the platform drifts off the collimation axial in laser resonator, it will affect the laser from normal working. Generally, a complicated laser system has many optical mounts, accumulated drift of all adjustable elements will decrease laser’s output, even lead to stop lasing. In this paper, we proposed a method that is suitable for measuring stress relaxation of precision diskspring used for laser optical mounts, comparing with normal experimental facilities for diskspring’s stress relaxation test. We use a simple optical path design, which can not only be intuition, but also measure the diskspring’s creep deformation easily with high accuracy. Comparative experimental results for the creep deformation between no prestressing, treated by 5 short terms prestressing and treated by 24 hours prestressing are given. We found that the stress relaxation amount with prestressing is 1/12 of those without prestressing, and they change directly into the stable creep deformation stage, and can be used safely. This paper also gave a instruction to optical mount manufacturer that after the optical mount are assembled, tightening adjusting screw and keeping all the disksprings in a compacted state for 24 hours, then releasing before ex-factory, this is the best way to reduce stress relaxation in diskspring and will achieve higher stability of laser.
Influence of phase error of optical elements on optical path design of laser facilities