阐明了一种利用腔的临界稳定条件来测量灯抽运大功率连续Nd:YAG激光器有效热透镜焦距的简单方法。通过测量特殊临界稳定点的输出功率,可计算出激光棒的有效平均热焦距,以及径向和切向的热透镜焦距fr和fθ。此方法简单可行,特别适用于高功率激光器热焦距的测量。此方法利用腔的临界稳定点,是在有激光输出时测量的,比无激光输出时更接近实际情况,与探测光束法比较测量偏差为±10%,小于非稳腔法±20%的测量偏差,测量值更准确。为优化设计大功率激光器提供了准确的设计参数。

A simple method using resonator critical stable point is applied to measure the thermal lens focal length of a flashlamp-pumped continuous wave (CW) Nd:YAG (Nd:Y3Al5O12) laser. By measuring output power at special critical stable point, the laser rod thermal lens focal length can be calculated. The method can also be used to obtain the thermal lens radial and tangent focal length, fr and fθ, respectively. This method is simple and practical, it is applicable especially for the measurement of thermal focal length of high power laser. Because of using the critical point of the resonator with laser on, this method is closer real case than without laser, the measurement is more accurate. The measuring deviation of the method comparing with probe beam method is within the order of ±10%. It is less than that of the unstable-resonator method that is in the order of ±20%.