Determination of thermal focal length and pumping radius in gain medium in laser-diode-pumped Nd:YVO4 lasers

Abstract

A method to determine the focal length of a thermal lens and pumping laser beam waist in the gain medium in laser-diode-pumped solid-state lasers is presented. This method, using resonator transform circle theory, is both simple and reliable. The measured focal length of the thermal lens is used to calculate the beam waist of pumping laser inside the gain medium. The effect of the thermal lens on the output power is also measured and analyzed.

12 W high efficiency single frequency ring laser

“…In the experiment, in order to obtain the higher beam overlap efficiency, we increase the diameter of the laser in the case of retaining the TEM 00 output; and choice the transmission of the couple mirror for the higher extraction efficiency, and choice the components with the least single-pass losses for the higher coupling efficiency [12]. At last, we obtain the high efficiency which is close to the limit of the efficiency.…”

Efficient continuous-wave intracavity frequency-doubled Nd:YAG-LBO blue laser at 473 nm under diode pumping directly into the emitting level

“…The radius in the middle of LBO is about 60 μm, which would yield good frequency doubling efficiency. When the absorbed pump power at 885 nm was 18.7 W, the thermal-lens focus length of the Nd:YAG crystal was about 200 mm measured by a method, which used the transform circle theory of resonator proposed in [18]. We can see that the Nd:YAG laser is still in the stability zone when it is operated with the maximum pump power from Fig.…”

Self-compensation of thermal lens in high-power diode pumped solid-state lasers

“…However, due to certain fundamental physics mechanisms, e.g., the quantum defect and fluorescence quenching, it is inevitable that larger amount absorbed energy transfer into the heat in the laser material, which produces an uneven temperature field and greatly reduces the beam quality [2]. Therefore, it has been a long-term active subject to study the heat-generation mechanism and its interaction with other physics mechanisms in the solid-state lasers [3][4][5][6]. In the present paper we point out a remarkable physical phenomena, that there is coupling between lasers and thermodynamics of gain medium in high-power DPSSL running in (quasi-)continuous mode.…”