Nd:YAG陶瓷与单晶4F3/2–4I13/2跃迁的弱谱线多波长激光性能对比

报道了基于半导体激光端面抽运Nd:YAG的⁴F_3/2–⁴I_13/2 跃迁的弱谱线多波长激光输出. 实验对比了透明陶瓷与单晶材料的激光输出特性, 表明透明陶瓷和单晶材料荧光谱强度的略微差异, 导致了多波长输出时相同两个波长之间的激光强度比在两种材料中的差异. 基于两种耦合输出镜片, 激光阈值都在2 W左右. 在13.5 W的抽运功率下, 基于Nd:YAG透明陶瓷获得了输出功率4.05 W、强度比1 :2的1338与1356 nm双波长激光和输出功率3.65 W、强度比13 : 1的1356与1414 nm 双波长激光, 斜率效率分别达33.9% 和31.9%.

Multiple weak-line laser operation from Nd:YAG 4F3/2-4I13/2 translation in ceramic and crystal

Laser diode end-pumped Nd:YAG based multiple weak-lines laser from ⁴F_3/2-⁴I_13/2 translation is reported. Fluorescence spectra for both Nd:YAG crystal and ceramic are present. Simple two-mirror cavity with reasonable optical coating is used for multiple weak-line laser operation around 1.3 and 1.4 μm. The variations of laser output and spectra with the pump power are compared experimentally between 1.0 at.% Nd³⁺ doped Nd:YAG ceramic with 3 mm×3 mm×7.5 mm in size and 0.8 at.% Nd³⁺-doped Nd:YAG crystal with 3 mm×3 mm×8 mm in size. First, 1338 and 1356 nm dual-wavelength laser outputs are achieved using output coupler with transmittance values of 9.6%, 6.2%, 2.4% and 1.8% at 1338, 1356, 1414 and 1444 nm, respectively. Under low pump power around the threshold, the 1356 nm single wavelength laser is obtained. With increasing the pump power, the laser with a wavelength of 1338 nm appears first in the ceramic. At an incident pump power of 11.8 W, a 1338 and 1356 nm dual-wavelength laser with an output power of 3.7 W and an intensity ratio of 1 : 5 for crystal, and a 1338 and 1356 nm dual-wavelength laser with an output power of 3.5 W and an intensity ratio of 1:3 for ceramic are obtained. Replacing the output couplers with transmittance values of 15.4%, 6.5%, 1.1% and 0.8% at wavelengths of 1338, 1356, 1414 and 1444 nm, respectively, 1356 and 1414 nm dual-wavelength laser outputs are achieved. Under the low pump power, even triple-wavelength (1356, 1414 and 1444 nm) laser is obtained. With increasing the pump power, the intensities of 1414 and 1444 nm wavelengths turned down and the 1444 nm wavelength disappears first in ceramic. At an incident pump power of 11.8 W, a 1356 and 1414 nm dual-wavelength output power of 3.56 W with intensity ratio of 44 : 1 for crystal and a 1356 and 1414 nm dual-wavelength laser output power of 3.25 W with intensity ratio of 12 : 1 for ceramic are obtained. The results show that slight difference between fluorescence spectra results from the difference in laser spectrum between transparent ceramic and single crystal materials for multi-wavelength output. Thresholds of two different output couplers are both about 2 W. When the incident pump power increases to 13.5 W, a 1338 and 1356 nm dual-wavelength laser output power of 4.05 W and a 1356 and 1414 nm dual-wavelength laser output power of 3.65 W are achieved in Nd:YAG transparent ceramic. The corresponding slope efficiency values are 33.9% and 31.9%, respectively.