中国一网激光技术有限公司提供美国NEOS系列Q开关（声光Q头）:33027-50-5-I-
英国古奇系列Q开关（声光Q头）:GOOCH&HOUSEGO系列Q开关（声光Q头） :I-QS027-3C4G-U5-ST1，法国AA系列Q开关（声光Q头）:AA.QS27-A5-S1064-WSC
国产系列Q开关（声光Q头）。
水冷Q开关使用注意事项
由于使用不当致使Q开关损坏的情况都不属于保修范围，所以用户在使用过程中一定要注意以下情况。
1.Q开关需要在清洁干燥的环境中使用，不能在太潮湿或很多灰尘的地方使用。如有灰尘或水珠落在镀膜晶体表面污染晶体，由于很高的激光功率密度会使表面烧坏。建议在光路中使用塑料或金属管密封光路和Q开关的两端。 2.Q开关镀膜表面不可以有手印污染，也不可以对着镀膜表面讲话或哈气，以免水汽或唾液污染表面。 3.Q开关必须通水冷却，短时的断水都有可能烧坏Q开关。建议使用自动断水保护开关，当然使用Q开关自带的温度保护开关。 4.对于旧款的Q开关，应该使用去离子水冷却Q开关，不得使用其它的水（如饮用水等）。否则，Q开关水路容易腐蚀并产生堵塞。新款的牧马系列Q开关可以用普通水冷却。 5.Q开关的匹配阻抗是50欧姆，必须使用输出为50欧姆的驱动电源和同轴电缆。注入射频电源的频率必须是与Q开关要求的频率一致，且注入射频功率不能超过100W。
Q switch maintenance
The acousto-optical Q-switch often used in the laser marking makes use of mutual interaction between an ultrasonic wave and a light beam in a scattering medium. The light beam that enters in a direction forming a Bragg angle to the wave surface of the acoustic wave in the scattering medium is diffracted in accordance with periodic changes in the diffraction rate produced by the acoustic wave.
The situation is briefly explained in Figure 1. First of all, an RF signal is impressed to the transducer adhered to the molten quartz and thickness extensional vibration is produced. Ultrasonic shear waves are caused to advance in the molten quartz by this vibration, and phase grating formed by acoustic waves is produced. The laser beam is diffracted when it satisfies the Bragg angle with respect to this phase grating, and is separated in space from the incident light.
Figure 1: Principle of A-O Q-switch
If the laser optical resonator is constructed against 0-dimensional diffracted light (undiffracted light), the diffracted light deviates from the laser optical resonator axis when a RF signal is impressed. As a result, loss occurs in the laser optical resonator and laser oscillation is suppressed. To make use of this phenomenon, an RF signal is impressed for a certain length of time only (status of low Q-value) to suspend laser oscillation. In the meantime, the population inversion of the Nd:YAG rod is accumulated by continuous pumping. When the RF signal is reduced to zero (status of high Q-value) and the loss to the laser optical resonator is removed, the accumulated energy is activated as laser oscillation in a pulse form within an extremely short length of time. They are Q-switch pulses.
This situation is briefly explained in Figure 2. When an RF signal is subjected to pulse modulation, it is possible to periodically take out a Q-switch pulse. When the period of Q-switch pulses becomes shorter than the life (about 200 ms) of the higher order of the Nd:YAG rod, however, the population inversion decreases and the peak value of Q-switch pulses decreases. | 
