检查逻辑并润色下面这段话高功率紧凑型Tm：YAG激光实验装置如图1所示主要由一个三向侧面抽运结构的激光模块和两个平面镜组成。TmYAG晶体棒的尺寸为varphi3 mm×74 mm晶体的掺杂区域仅有36 mmTm3+的掺杂浓度原子数分数为3。为了减少重吸收损耗14棒两端各键合有19 mm未掺杂的YAG并且端面均镀有2020 nm增透膜以提高透过率。晶体棒被安装在内径为45 mm厚度为1 mm的石英

The high-power compact Tm:YAG laser experimental setup is shown in Figure 1, consisting of a laser module with a three-way side-pumping structure and two flat mirrors. The Tm:YAG crystal rod has dimensions of φ3 mm × 74 mm, with a doping region of only 36 mm and a doping concentration (atomic fraction) of 3% for Tm3+. To reduce reabsorption losses [14], there are 19 mm of undoped YAG at each end of the rod, and both end faces are coated with 2020 nm anti-reflection film to increase transmission. The crystal rod is mounted in a quartz tube with an inner diameter of 4.5 mm and a thickness of 1 mm, and the heat generated by the crystal is taken away by cooling water. Three LD Bar strips (Focus Light, USA) are symmetrically distributed at 120° around the surface of a ceramic diffuse reflector with an inner diameter of 5.5 mm and a thickness of 0.5 mm. Each Bar strip is directly mounted on a copper heat sink, and cooling water flows over the surface of the heat sink to control the temperature of the Bar strip. A single laser module can provide an excitation power of approximately 660 W at maximum driving current. The fast axis divergence angle of the LD is 35°, and the distance between the emitting surface and the axis of the crystal rod is designed to be 6 mm, which ensures that almost all excitation light can be directly absorbed by the crystal, thereby improving the absorption efficiency. The laser module adopts a single-channel water-cooled structural design, using a water chiller to cool both the LD Bar strip and the Tm:YAG crystal simultaneously. The cooling water flow rates for the LD Bar strip and the crystal rod during the experiment are 4.5 L/min and 8 L/min, respectively, and the cooling temperature is 12 ℃. Tm:YAG has two absorption bands, located near 781 nm and 785 nm, respectively [15]. The center wavelength of the LD Bar strip we selected is 780.5 nm at maximum driving current, and the full width at half maximum (FWHM) of the emission spectrum is approximately 1.7 nm, so the wider 781 nm absorption band of Tm:YAG can be matched over a larger range of driving currents. The resonant cavity consists of two flat mirrors, with M1 coated with a 2020 nm high-reflection film and M2 as a coupling output mirror with a transmittance of 7.8% at a wavelength of 2020 nm. The distance between the two cavity mirrors and the end faces of the crystal rod is 7 mm, and the total cavity length is 88 mm