RESUMEN
Optical thermometry based on the upconversion (UC) luminescence intensity ratio (LIR) has attracted considerable attention because of its feasibility for achievement of accurate non-contact temperature measurement. Compared with traditional UC phosphors, optical thermometry based on UC single crystals can achieve faster response and higher sensitivity due to the stability and high thermal conductivity of the single crystals. In this study, a high-quality 5 at% Yb3+ and 1 at% Ho3+ co-doped Gd0.74Y0.2TaO4 single crystal was grown by the Czochralski (Cz) method, and the structure of the as-grown crystal was characterized. Importantly, the UC luminescent properties and optical thermometry behaviors of this crystal were revealed. Under 980 nm wavelength excitation, green and red UC luminescence lines at 550 and 650 nm and corresponding to the 5F4/5S2 â 5I8 and 5F5 â 5I8 transitions of Ho3+, respectively, were observed. The green and red UC emissions involved a two-photon mechanism, as evidenced by the analysis of power-dependent UC emission spectra. The temperature-dependent UC emission spectra were measured in the temperature range of 330-660 K to assess the optical temperature sensing behavior. At 660 K, the maximum relative sensing sensitivity (Sr) was determined to be 0.0037 K-1. These results highlight the significant potential of Yb,Ho:GYTO single crystal for optical temperature sensors.
RESUMEN
We report on a high-peak-power electro-optically Q-switched laser emitting a near-diffraction-limited beam profile at 1064 nm by using a gradient-doped Nd:YAG crystal. The gradient-doped crystal features a unique combination of a reduced thermal lens effect through effectively spreading the heat load distribution within its volume. Its performance is compared with those of Nd:YAG crystals with uniform volume doping distribution operating in the Q-switched regime with the same laser configuration, demonstrating the higher average and peak power achievable with the gradient-doped crystal. The maximum average output power amounts to 6.9 W at a pulse repetition rate of 2 kHz, which corresponds to a maximum peak power of â¼585kW. Compared to homogeneous dopant crystals, the slope efficiency and average output power increased by 30.8% and 21.1%, respectively.
RESUMEN
In this paper, we present the acousto-optical (AO) Q-switched performance of a holmium (Ho):gadolinium tantalate (GdTaO4) (Ho:GTO) laser pumped by a thulium (Tm)-fiber laser emitting at 1.94 µm. In the efficient continuous wave (CW) regime, a maximum output power of 30.5 W at 2068.8â nm was achieved, corresponding to a slope efficiency of 74.9% with respect to the absorbed pump power. In the Q-switching regime, pulse energies of 2.4 mJ, 1.2 mJ, and 0.9 mJ were obtained with pulse repetition frequencies of 10 kHz, 20 kHz, and 30 kHz, respectively. The minimum pulse widths were 18â ns, 23â ns, and 26â ns, corresponding to peak powers of approximately 133.3â kW, 52.2â kW, and 34.6â kW, respectively.
RESUMEN
Based on Faraday effect we demonstrate a thulium fiber pumped continuous-wave single-longitudinal-mode laser with a new Ho:GdTaO4 crystal. By inserting a faraday rotator and a half-wave plate into the laser cavity, the single-longitudinal-mode output power of 392â mW at wavelength of 2068.33â nm was obtained in unidirectional Ho:GdTaO4 ring laser, corresponding to a slope efficiency of 60.2% respect to the absorbed pump power. Furthermore, utilizing the Ho:GdTaO4 power amplifier, the maximum single-longitudinal- mode output power of 1.02 W was achieved.
RESUMEN
An erratum is presented to correct the wrong picture in our paper.
RESUMEN
We demonstrate a continuous-wave 2.1-µm laser with a new Ho:GdTaO4 crystal pumped by a 1940.3-nm Tm fiber laser at room temperature. The maximum output power of 11.2 W at 2068.39 nm was achieved, corresponding to a slope efficiency of 72.9%. Moreover, the beam quality factor was measured to be about 1.4 at the maximum output level.
RESUMEN
We demonstrated an 879-nm-diode-pumped Nd:Gd0.69Y0.3TaO4 laser in continuous-wave-(CW), pulse-pumped, pulse-reflection-mode Q-switched, and cavity-dumped burst-mode Q-switched operations for the first time. A maximum output power of 9.3 W at 1,066 nm was obtained in the CW operation with a slope efficiency of ~48%. The slope efficiency reached the value of ~68% in the pulse-pumped operation. A peak power of 150 kW and pulse width of 3.4 ns were obtained in the cavity-dumped burst-mode Q-switched operation at a Q-switching repetition rate of 20 kHz.
RESUMEN
Laser performances around 1.3 µm are investigated in 879 nm laser diode (LD) end pumped Nd3+ doped mixed crystals with Nd:Gd0.69Y0.3TaO4 and Nd:Gd0.68Y0.3NbO4 crystals for the first time to our best knowledge. The maximum average power in LD end pumped Nd:Gd0.69Y0.3TaO4 1328 nm laser reaches 435 mW at 50 Hz with an optical-to-optical efficiency of 5.0% and a slope efficiency of 6.9%. In comparison, the highest average power of LD end pumped Nd:Gd0.68Y0.3NbO4 laser at 1337 nm is 190 mW at 50 Hz, corresponding to an optical-to-optical efficiency of 3.5% and a slope efficiency of 4.2%.
RESUMEN
We demonstrate a 968 nm diode end-pumped Er,Pr:GYSGG (Gd1.17Y1.83Sc2Ga3O12) laser at 2.79 µm operated in the pulse and continuous-wave (CW) modes. The lifetimes for the upper laser level 4I11/ 2 and lower level 4I13/2 are 0.52 and 0.60 ms, respectively. The laser produces 284 mW of power in the CW mode, corresponding to the optical-to-optical efficiency of 14.8% and slope efficiency of 17.4%. The maximum laser energy achieved is 2.4 mJ at a repetition rate of 50 Hz and pulse duration of 0.5 ms, corresponding to a peak power of 4.8 W and slope efficiency of 18.3%. These results suggest that doping deactivator Pr3+ ions can effectively decrease the lower-level lifetime and improve the laser efficiency.
