Due to 2 μm band in the absorption of water and CO<sub>2</sub>, the diode pumped solid state lasers with wavelength around 2 μm have important applications in laser medicine and remote sensing, such as it can be used as a scalpe or a light source of Coherent Doppler Wind Lidar and Differential Absorption Lidar. In the recently years, scientists have done much work on the development of such lasers. There’re many reports on continuous Tm:YAG laser. However, the study on Q-switched Tm:YAG laser, which is more useful in applications, was very rare. As the light source of Coherent Doppler Wind Lidar, large energy and wide pulse width is desired. Current reports mostly adopted CW pumped source, but it would make a mount of heat. Pulse pumping method could reduce the heat accumulation and improve the heat stability of the laser. How to improve the single pulse energy was the focus of current study. In this paper, a single end bonding Tm:YAG crystal with Tm<sup>3+</sup> doping concentration of 3.5at.% was used. Acousto-optic (AO) Q-switched (GOOCH and HOUSEGO QS041-10M-HI8) operation was adopted in our experiment. In the repetition frequency of 100Hz, a maximum single energy of 2.67 mJ (measured by Ophir 30A-BB) and the narrowest pulse width of 149 ns (measured by Vigo PCI-3TE-12 detector) were achieved at room temperature. The M<sup>2</sup><sub>x</sub> was 1.31 and the M<sup>2</sup><sub>y</sub> was 1.35 (measured by Spiricon Pyrocam-III). Tm:YAG laser was developed by using a pulse diode pumped L shape resonant cavity. The transmittance of the curve output mirror was 4% and the curvature radius of which was 300 mm. The output center wavelength of the laser was measured to be 2013.5 nm (measured by YOKOGAWA AQ6375).
A mid-infrared optical parametric oscillator (OPO) with an idler wavelength of 3.85 μm at a repetition rate of 200 kHz is presented, and a high-repetition-rate electro-optic (EO) Q-switched Nd∶GdVO 4 laser with a double-crystal RbTiOPO 4 EO modulator is used as the pump source. The OPO is designed as an extracavity singly resonant optical parametric oscillator. The threshold value of the OPO system is only 1.3 W at 1.06 μm. When the MgO: periodically poled lithium niobate (MgO: PPLN) crystal is operated at 90°C and the pump power is 10.5 W with a repetition of 200 kHz, a maximum average output power of 1.82 W at idler wavelength of 3.85 μm and pulse width of 14.3 ns are obtained. The slope efficiency of the 3.85-μm laser with respect to the pump laser is 21.3%. The M 2 factors of the 3.85-μm laser are 1.84 and 1.76 in the parallel and perpendicular directions, respectively. The mid-infrared tunability of 3.7 to 3.9 μm can be achieved by adjusting the temperature of MgO∶PPLN crystal from 210 to 35°C.
We report on a LD dual-end-pumped 792nm continuous wave operation Tm:YLF laser. Firstly, the rate equation of LD end-pumped CW operation Tm:YLF laser were established, in which the energy transfer upconversion and without energy transfer upconversion under continuous-wave considerate were considered, as well the pump threshold and the slope efficiency of the laser system were analyzed. Simultaneously, the cavity stability condition and the pattern matching of the plano- concave resonator were analyzed according to ABCD Matrix theory. Comparing respectively the laser threshold and the slope efficiency and optical-optical conversion efficiency under circumstances which the output mirror transmittance of 15% and 23%. In addition, the M2 of the output laser were contrasted and analyzed in adjusting the resonator cavity length by using different radius of curvature of the output mirror in 150mm, 200mm and 300mm all in the above case. As the process of thermal lens focal length changing greater than 90mm, it exhibited that the two fundamental modes in the cavity resonator matched well in numerical simulation when the radius of curvature of the output mirror was 300mm, as well the two fundamental modes matched well when it more than 100mm in a certain pump power. We designed a single LD dual-end-pumped continuous wave operation Tm:YLF laser. Using Tm:YLF (3 at.%) crystal for gain medium, which the size was 3×3×14mm<sup>3</sup>. In experiments, the Tm:YLF laser crystal keeps 291K and the temperature control method is water cooling. The length of the resonator was 135mm when L shape plano-concave resonator was applied, and the radius of curvature output mirror was 300mm, as well as the temperature of the Tm:YLF laser crystal was 291K. The output laser we observed by this system and the central laser wavelength was 1944nm. The threshold power was 8.11W and the highest output power reaches to 4.01W when the totally input pump power was 17W, and the optical conversion efficiency was 23.6%. The far-field divergence angle was 3.8mrad after calculation. Respectively. The experimental results are coinciding with the theory.
It report a continuous wave Ho:YAG laser pumped by1.91 μm Tm Laser. It important to thesis
analyzed the output characteristics of Ho laser pumped by continuous Tm laser.The rate equation of Ho
laser in continuous-wave operation was put forward. The rate equation was solved to analyze the
influence of upconversion effect to the output power, slope efficiency and threshold power in CW
operation .The transition branching ratio between the energy levels was taken into consideration while
discussing the influence of up conversion.Through the simulation analysis on the output characteristics,
consider the influence of upconversion effect than to ignore the influence of upconversion effect, The
threshold power increased by 0.34W, the highest output power of the reduced 2.89W, the slope
efficiency was decreased by 16.1%.Respectively，For all the experiments, the Tm:YLF laser crystal
keeps 292K and the temperature control method is water cooling. When we applied L shape plano
concave resonator, the length of the resonator is100mm, the radius of curvature output mirror is
150mm and the temperature of theHo:YAG laser crystal is 292K, we observed the central laser
wavelength is 2.09μm. The highest output power reaches 8.23W when the totally input pump power
is18W. And the slope efficiency is 45.7%, respectively. The experimental results are coincide with the
In this paper, we present a compact 803 nm diode side-pumped Nd:YAP laser that can produce 86 W of polarized
1341.4 nm output in continuous-wave mode. The laser characteristics including thermal lens and different cavity
types were studied. By comparing the output powers at different resonator lengths and different output couplers, 86
W output power with c-axis polarized laser at 1341.4 nm has been obtained at the maximum pumping power of 840
W. The optical-optical efficiency is 10.2% and the slope efficiency is 16.6%. The beam quality factors of the 1341.4
nm laser are 13.26 and 13.54 in the parallel and perpendicular directions, respectively.
The laser diode side-pumped electro-optical Q-switced Nd:YAG laser of high single pulse output energy were studied.
Two alternated semicircular LDA module was used to directly side pump the Nd:YAG crystal of a series of two-rod.
Each module consists of 30 laser diode which peak power is 100W. KD*P crystals is used as the electro-optic Q switch.
And the ABCD law of the Gaussian beam propagation is applied to calculate the area of the stability of the resonator
cavity, and a more reasonable parameters of the resonant cavity is given. A 1064nm dynamics laser that maximum output
energy of 140mJ and pulse width of 10ns is obtained at a repetition rate of 20Hz when the pump energy is 1200mJ.The
optical-optical conversion efficiency is 11.7%.