Research On Characteristics Of 1342nm Innoslab Amplifier And 946nm Laser At Low Temperature Based On The Directly Pumped

High-power solid-state laser is an important development direction of high-tech laser technology,and it urgently needs the laser with high-power and high beam quality.The basic way to achieve this goal is to improve the efficiency and reduce the thermal effect.Developing the direct pumping laser technology is the key to solve the problem.With the development of direct pumping technology,only using the direct pumping method has been difficult to meet people's requirements for high power and high efficiency.In this paper,based on the direct pumping Nd ion laser technology,experimental studies have been conducted on the direct pumping Nd ion laser technology in combination with the direct pumping technology and the Innoslab crystal structure.The main achievements are described as follows:1.For the problem of serious deterioration of the beam quality with the rod-shaped Nd:YVO₄crystal amplifier,a compact and efficient 880 nm pumped 1342 nm Nd:YVO₄ partially pumped slab?Innoslab?picosecond amplifier was demonstrated.Combined with the advantages of the direct pumping technique and Innoslab structure,a 20 W,24.6 ps laser output at 1342 nm was achieved at the absorbed pump power of 175 W with the extraction efficiency of 8.5%.The corresponding output beam quality was measured with M²=1.65.2.The performance of the 946 nm quasi-three-level laser pumped by 885 nm pumped Nd:YAG crystal at low temperature was studied.The Boltzmann distribution fraction of the upper and lower laser levels as a function of temperature was introduced into the laser rate equation,and the small signal gain and laser threshold at low temperature were analyzed.We developed a cryogenic system to study the output characteristics of the 946nm laser at low temperature.A maximum 165 mW laser output with the slope efficiency 36%was achieved at 210K.The slope efficiency was increased by 71%compared with the room temperature operation.The gain of 1061 nm laser enhanced at low temperature was observed and analyzed.When the temperature is lower than 190K,the gain of the 1061 nm laser significantly increases and competes with the 946 nm laser,resulting in a decrease in the 946 nm laser output.