Study On The Characteristics Of The Diffraction Efficiency In A-O Q-switched DPL

The diffraction capability of the Acousto-optical Q-switch has effect on the characteristics of the output pulse in the high-gain DPL (diode pumped solid-state laser). This paper is mainly on the diffraction efficiency when incident light is non-paralleled and the effect of the diffraction efficiency variation rate on temporal characteristics of the output pulse.The distribution of diffraction efficiency was measured experimentally when the incident light is non-Gaussian and the incident location is not at the waist, and was calculated with the method of angle-spectrum conception, it yields that the maximize diffraction efficiency can not be obtained when the incident location is at the waist for a stable incident light distribution. This method offers a reference to calculate diffraction efficiency for a more common incident light distribution.Then, the paper deals with the effect of the diffraction efficiency variation rate on the time required for the laser pulse to build up and the shape of the pulse. The effect of constant and variable diffraction efficiency variation rate on the characteristics of the output pulse according to the experimental situation. It is found that the existence of the effect of the diffraction efficiency variation rate on the characteristics of the output pulse is depended on the matching of the time required for the laser pulse to build up and the switching time. So the diffraction efficiency variation rate and parameters that affect the time required for a laser pulse to build up can be selected for practical need to minimized the effect of the diffraction efficiency variation rate on the quality of the output pulse.