Lingxiong Huang

Efficient second harmonic generation of double-end diffusion-bonded Nd:YVO4 self-Raman laser producing 7.9 W yellow light

A high power and efficient 588 nm yellow light is demonstrated through intracavity frequency doubling of an acousto-optic Q-switched self-frequency Raman laser. A 30-mm-length double-end diffusion-bonded Nd:YVO(4) crystal was utilized for efficient self-Raman laser operation by reducing the thermal effects and increasing the interaction length for the stimulated Raman scattering. A 15-mm-length LBO with non-critical phase matching (theta = 90 degrees, phi = 0 degrees) cut was adopted for efficient second-harmonic generation. The focus position of incident pump light and both the repetition rate and the duty cycle of the Q-switch have been optimized. At a repetition rate of 110 kHz and a duty cycle of 5%, the average power of 588 nm light is up to 7.93 W while the incident pump power is 26.5 W, corresponding to an overall diode-yellow conversion efficiency of 30% and a slope efficiency of 43%.

Efficient 532 nm laser using high gray-tracking resistance KTP crystal

A LD end-pumped acoustic-optic Q-switched intracavity frequency-doubled Nd:YVO4 laser was demonstrated. It uses a high gray-tracking resistance KTP crystal as nonlinear optical crystal. The output characteristics of 532 nm green laser using different doping concentrations and cavity configurations were investigated. With the pump power of 27.5 W, a maximum average power of 13 W at 532 nm was achieved at a pulse repetition rate of 80 kHz, corresponding to the optical-to-optical efficiency of 47.3%. The pulse width is 30 ns and single pulse energy is up to 162.5 μJ. This work is a significant exploration for using a high gray-tracking resistance KTP crystal to generate highly efficient frequency-doubled green laser.

Growth and optical properties of UV transparent YAB crystals

Abstract Large and ultraviolet (UV) transparent YAl3(BO3)4 (YAB) crystals were grown by a high temperature top seeding method with Li2B4O7–AlBO3 as the flux. The UV cutoff wavelength of the YAB crystal was shorter than 190 nm. The refractive indices of the YAB at several wavelengths covering UV–visible and near infrared wavelength over the temperature range from 30 to 170°C were measured by the autocollimation method. The parameters of the Sellmeier dispersion equation were determined based on the experimental data. The phase matching curve of second harmonic generation was measured. The deviations of the phase matching angle for second harmonic generation at 473 nm as a function of temperature for the YAB crystals were investigated. The coefficient of frequency doubling d11 of the YAB crystal was measured to be 1·30 pm V−1 by a phase matching method.

Diode-side-pumped Nd:YAG laser at 1338 nm

In this Letter, a high-power diode-side-pumped Nd:YAG laser emitting at 1338 nm is described. The output characteristics of the laser using the different output couplers for both the cw mode and the Q-switched mode have been studied. With a pumping power of 555 W, the average output power decreases from 70 W at 50 kHz to 55 W (slope efficiency 21.2%, optical conversion efficiency 10%) at 5 kHz. The highest peak power is up to 73 kW with the pulse duration of 150 ns at the repetition rate of 5 kHz. When operated in cw mode, the output power of 100.5 W was achieved, corresponding with the optical slope efficiency of 36%.

Growth and optical properties of nonlinear LuAl 3 (BO 3 ) 4 crystals

The optical properties of pure LuAl(3)(BO(3))(4) (abbreviated as LuAB) crystals were investigated for the first time. Large UV-transparent LuAl(3)(BO(3))(4) crystals were grown by a high-temperature top-seeding method with Li(2)WO(4)O(7)-B(2)O(3) as the flux. The refractive indices of LuAl(3)(BO(3))(4) at several wavelengths covering ultraviolet-visible and near-infrared regions were measured by the auto-collimation method. The parameters of Sellmeiers dispersion equation were determined from the experimental data. The phase-matching curve of second harmonic generation was measured. The nonlinear optical coefficient d(11) of LuAB crystal was determined to be 1.10 pm/V by a phase-matching method. The UV cut-off wavelength of the LuAl(3)(BO(3))(4) crystal was shorter than 190 nm.

The study of 670.7 nm red light generated by intracavity frequency doubling of a Q-switched Nd : YAlO3 laser

High-power 670.7 nm red light was obtained by intracavity frequency doubling of a Q-switched Nd : YAlO3 (Nd : YAP) laser with a critical phase matching (θ = 85.9°, = 0°) cut LBO. Experimental configurations using V-cavity and Z-cavity have been adopted for comparison. The highest output power of 19.7 W was achieved in the Z-cavity with optical–optical efficiency of 4%. Compared with the laser using an Nd : YAG crystal, the adoption of Nd : YAP simplified the laser system in the absence of a solid etalon and the Brewster plate. The output power stability of the red laser was investigated and the fluctuation was lower than 3% at the output power of 18 W an hour.