Low Evolution X output power

The Evolution -- the DPSS Q-switched green laser is used to pump the Ti:sapphire crystal for regeneration amplifier of 30 fs laser pulses. However its output power was dropped dramatically when we operated it this morning. The power could not be changed very much when we tuned two cavity mirrors. Later we adjusted the diodes temperature between 80F and 83F, the power just fluctuated from 22mW to 18mV when the output was set at 23%. In the normal way, the power should be around 600mW.