The thermal lens and temperature-gridient-induced light deviation at a long-pumped Nd:YAG laser rod are measured.A high-speed camera is used to capture the spot size and movement generated from a TEM00 mode He-Ne laser with 5 kHz frame rate.Dynamic focal length of thermal lens and light deviation angle is computed with light transfer matrix,q parameter and ABCD law.The tests show that the thermal lens is negative during the pumping,and the greater the pump intensity,the shorter the focal length;the minimum ...