A comparative study on diode-pumped single-frequency Tm:YAG and Tm:GdVO<Subscript>4</Subscript> lasers

In this paper, we present experimental results concerning on the laser characteristics of Tm:YAG laser and Tm: GdVO₄ laser. At room temperature, the maximum output power of Tm:YAG laser and Tm:GdVO₄ laser is 210 and 145 mW, respectively. High efficiency can be achieved for both lasers at room temperature. Nevertheless, compared with Tm:GdVO₄ laser, Tm:YAG laser can operate on single frequency with high power easily. As much as 60 mW of 2013.9 nm single-longitudinal-mode (SLM) laser was achieved for Tm:YAG laser. For Tm:GdVO₄ laser 51 mW of 1919.7 nm SLM laser was achieved. The SLM Tm:YAG laser is better for using as a seed laser for coherent wind measurements and differential absorption LIDAR systems.     

High-efficiency composite Tm:YAG laser

A high-efficiency continuous-wave Tm:YAG laser end-diode pumped at room temperature is presented in this letter. The highest output power reaches 6.37 W when the incident pump power is 18.9 W. The optical conversion efficiency is 33.7% and the slope efficiency is 42.8%. The wavelength of the output laser is shifted to the short wavelength with an increase in the transmission of the output couplers. At a fixed cavity length, the composite Tm:YAG shows its dominance for its higher efficiency and higher quantum efficiency compared with the noncomposite Tm:YAG.     

End-Pumped Tm:YAG Ceramic Slab Lasers

Lasers from a Tm：YAG slab is end-pumped by continuous-wave output of the Tm：YAG ceramic ceramic am~e reported for the t~rst time to our best knowledge. The Tm：YAG ceramic a laser diode with central wavelength 792nm. At room temperature, the maximum power is 4.5 W, and the sloping efficiency is obtained to be 20.5%. The laser spectrum is centered at 2015nm.     

2-W Ho:YAG laser intracavity pumped by a diode-pumped Tm:YAG laser

Efficient room-temperature operation of a Ho:YAG laser, intracavity pumped by a diode-bar-pumped Tm:YAG laser, is reported. At rod mount temperatures of 10 degrees C, for both the Tm:YAG and the Ho:YAG rods, we obtained 2.1 W of output at 2.097mum from the Ho:YAG laser for 9.2 W of diode power incident upon the Tm:YAG rod.     

Comparative study of LD-pumped Tm:YAG and Tim:LuAG lasers

Widely tunable performances of Tm:YAG and Tm:LuAG lasers near 2 μm are demonstrated. The emission spectra of Tm³⁺ in these two single crystals are reported and analyzed. The lifetimes of the ³ F ₄ state in thulium-doped YAG and LuAG are 10.1 and 9.2 ms, respectively. In addition, it is proven that the Tm:YAG crystal with two bonded undoped YAG ends is promising for high-efficient operation.     

Cr,Tm:YAG晶体中的能量转移

通过对Cr:YAG、Tm:YAG和Cr,Tm:YAG晶体吸收光谱和发射光谱的比较,研究了Cr,Tm:YAG晶体中的能量转移过程.指出Cr3+→Tm3+能量转移过程中,无辐射能量转移占绝对优势.     

Diode-pumped single-frequency Tm:YAG laser with double etalons

A diode end-pumped single-frequency Tm:YAG laser at room temperature is reported. The maximal output power of single-frequency is as high as 60 mW by using two uncoated fused YAG etalons, which are respectively 0.1 and 1.0 mm thick. We obtained a single frequency Tm:YAG laser at 2013.91 nm. The change of the lasing wavelength on temperature was also measured. The single-longitudinal-mode laser can be used as a seed laser for coherent wind measurements and differential absorption LIDAR systems.     

120-W continuous-wave diode-pumped Tm:YAG laser

We present a 120-W cw diode-pumped Tm:YAG laser. The Tm:YAG rod is side pumped by three diode arrays whose radiation is coupled through compound parabolic concentrators. The maximum optical-to-optical conversion efficiency of the 2.02-mum laser output is 25.2%, with a slope efficiency of 31.2%.     

纵向泵浦Tm：YAG激光器的理论研究

用准三能级系统速率方程对纵向泵浦Ｔｍ：ＹＡＧ激光器的阈值，效率和激活介质最佳长度进行了计算和分析，讨论了温度对Ｔｍ：ＹＡＧ激光器输出特性的影响。     

Room temperature diode-pumped Tm:YAG laser at 2008 nm

A diode end-pumped single-frequency Tm:YAG laser at room temperature was reported. The maximal output power of single-frequency is 30 mW by using two uncoated etalons. We obtained a single frequency Tm:YAG laser at 2008.14 nm. The single-longitudinal-mode laser can be used as a seed laser for coherent wind measurements and differential absorption LIDAR systems.     

Diode-end-pumped composite Tm:YAG rod with undoped ends at room temperature

The lasing characteristics of composite Tm:YAG rod with undoped ends at room temperature are reported. The maximum output power at 2.015 #m is 6.97 W and the slope efficiency is 41.45%. Focusing point and output coupler are changed to find the optimization condition. The relationship between operation temperature and output power is discussed. Comparison between Tm:YAG and composite Tm:YAG testifies the superiority of composite crystal.     

Fabrication and characterization of transparent Tm,Ho:YAG ceramic

Transparent Tm,Ho:YAG ceramic with excellent optical properties was fabricated by solid-state reaction method using high-purity commercial powders as raw materials. Optical absorption and 2.0 μm emission spectra of the ceramic specimen have been studied. The strongest emission corresponds to ⁵ I ₇ → ⁵ I ₈ transition of Ho³⁺ centered at 2.06 μm. As a result, Tm,Ho:YAG ceramic shows potential application in 2.0 μm laser devices.     

Tm:YAG晶体光谱的温度特性及荧光的温度淬灭

通过测量不同温度下Ｔｍ：ＹＡＧ晶体的吸收光谱、荧光光谱和荧光寿命发现,温度是影响Ｔｍ：ＹＡＧ晶体光谱特性的重要因素。温度升高不仅引起Ｔ：ＹＡＧ晶体吸收光谱、荧光光谱的加宽和新光谱线的产生,而且引起荧光淬灭现象的发生。     

Room-temperature operation of a multiwatt Tm:YAG laser pumped by a 1-mum Nd:YAG laser

We present what is to our knowledge the first demonstration of a 4.7-W cw Tm:YAG. This proof-of-principle experiment clearly demonstrates the possibility of using a pump absorption that is 2 orders of magnitude (~0.0078 cm(-1)) less than that of the conventional pump absorption (typically >1 cm(-1)). This Tm:YAG laser is pumped intracavity within a Nd:YAG laser for multiple-pass absorption. The maximum conversion efficiency of 2.02 mum is 20%, with a slope efficiency of 35% with respect to the absorbed 1.064-mum power.     

Single-frequency operation of a laser diode side-pumped Q-switched Tm:YAG laser using seeding injection technique

A laser diode (LD) side-pumped 2 μm single-frequency Q-switched Tm:YAG laser was demonstrated. The laser was injection seeded by a CW single frequency Tm:YAG laser with a twisted-mode cavity. The maximum single-frequency pulse energy was 16.3 mJ, with a pulse width of 570 ns and a pulse repetition rate of 10 Hz. The linewidth of the 2 μm single-frequency Q-switched laser was 0.68 MHz, measured by using the optical heterodyne technique. The M ² of the laser beam was measured to be 1.09 and 1.03 for x direction and y direction, respectively.     

Pulsed and cw Cr,Tm:YAG laser with simultaneous diode and flashlamp excitation

A Cr,Tm:YAG laser, under simultaneous flashlamp and diode laser excitation, was demonstrated. With respect to diode pumping a cw-output power of 35 W with a slope efficiency of 20% was achieved. With flashlamp excitation pulse energies up to 465 mJ were realised. This operation was supported by simultaneous diode pumping to bring the laser close to threshold. Repetition rates up to 10 Hz were demonstrated with this simultaneous pumping mode of the Cr,Tm:YAG laser crystal.     

Ho:YAG laser intracavity pumped by a diode-pumped Tm:YLF laser

We report a compact Ho:YAG laser that is intracavity pumped by a diode-pumped Tm:YLF laser. Both lasers exhibit pulse mode behavior. Operating both crystals at room temperature (25 degrees C), we obtained 1.6 W of average output at 2.09 microm from the Ho:YAG laser for 15.4 W of diode power incident upon the Tm:YLF rod and a slope efficiency of 21%.     

Tm：YAG晶体的光谱及激光特性研究

测试了Ｔｍ：ＹＡＧ晶体的室温吸收光谱和荧光光谱，计算了各吸收谱线的振子强度，并根据Ｊｕｄｄ－Ｏｆｅｌｔ理论了Ｔｍ：ＹＡＧ晶体的荧光跃迁截面和荧光寿命，用红宝石激光泵浦时，获得了波长２．０１μｍ能量４０ｍＪ的激光脉冲。     

Diode-pumped long-pulse-width Tm:YAG laser at room temperature

We report the pulsed-diode-pumped and acoustics-optically Q-switched operation of a long-pulse-width Tm:YAG laser at room temperature. Output energy for single pulse of 48 mJ is obtained under the incident pump energy of 217.3 mJ, corresponding to a slope efficiency of 30.2% and an optical conversion efficiency of 22.1%. For the Q-switched regime, maximum pulse energy of 3.25 mJ and the pulse width of 232.8 ns at the repetition rate of 30 Hz are achieved. The wavelength of the Q-switched laser is 2.013 μm. A beam quality factor of M ² < 1.4 is measured using the traveling 90/10 knife-edge method.     

Continuous-wave operation of a room-temperature Tm: YAP-pumped Ho: YAG laser

We report a continuous-wave (CW) 2.1-μm Ho:YAG laser operating at room temperature pumped by a diode-pumped 1.94-?m Tm:YAP laser.The maximum output power of 1.5 W is obtained from Ho:YAG laser,corresponding to Tm-to-Ho slope efficiency of 17.9% and diode-to-He conversion efficiency of 5.6%.