Hongyuan Shen

Comparison of simultaneous multiple wavelength lasing in various neodymium host crystals at transitions from 4F3/2–4I11/2 and 4F3/2–4I13/2

The possibility of simultaneous multiple wavelength lasing in various neodymium host crystals such as Nd:YAG, Nd:YLF, Nd:BEL, and Nd:YAP has been analyzed by the ‘‘oscillation condition.’’ It is shown that this kind of laser can be realized in all the described crystals in pulsed state, but only achieved in the Nd:YAP crystal in continuous‐wave state. On the basis of the analyzed results, we have achieved cw simultaneous multiple wavelength lasing in Nd:YAP crystal for the first time at both 1.0795 and 1.3414 μm.

Measurement of refractive indices and thermal refractive-index coefficients of LiNbO 3 crystal doped with 5 mol. % MgO

The principal refractive indices and the thermal coefficients for a LiNbO(3) crystal doped with 5 mol. % MgO have been measured by a minimum-deviation method for the wavelengths of 0.53975, 0.6328, 1.0795, and 1.3414, microm in the temperature range 20-154.5 degrees C. The constants of modified Sellmeier equations are all given in the described temperature range. The measured results were used to calculate the type I critical phase-matching angles for 1.0795- and 1.3414-microm second-harmonic generation at room temperature and the noncritical phase-matching temperature for 1.0795-microm second-harmonic generation for LiNbO(3) crystal doped with 5 mol. % MgO. The values obtained agree well with the experimental results.

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%.

Simultaneous multiple wavelength laser action in various neodymium host crystals

The oscillation condition of a simultaneous multiple wavelength laser has been established and used to analyze the possibility of simultaneous oscillation in various neodymium host crystals, such as Nd:YAG, Nd:YLF, Nd:BEL, and Nd:YAP crystals at the transitions from /sup 4/F/sub 3/2/-/sup 4/I/sub 13/2/ and /sup 4/F/sub 3/2/-/sup 4/I/sub 11/2/. It is shown that this kind of laser can be realized in all the described crystals in a pulsed state. In general, continuous wave (CW) operation, however, can only be achieved for Nd:YAP. On the basis of these results, CW simultaneous double wavelength lasing has been achieved in a Nd:YAP crystal for the first time at both 1.0795 mu m and 1.314 mu m. >

Measurement of the refractive index and thermal refractive index coefficients of Nd:YAP crystal

The principal refractive indices of yttrium aluminate crystal doping with 1-wt.% neodymium (Nd:YAP) have been measured by a minimum deviation method for the wavelengths 0.5398, 0.6328, and 1.0795 microm in the temperature range of 289-435 K. The thermal refractive index coefficients have been obtained at these wavelengths, and they are all positive and slightly decrease with increased wavelength. The constants of the single term Sellmeier equation are also given for the 273-420 K temperature range. These constants are in linear relationship with temperature in the 4 x 10(-3) error range.

Measurement of the stimulated emission cross section for the /sup 4/F/sub 3/2/-/sup 4/I/sub 13/2/ transition of Nd/sup 3+/ in YAlO/sub 3/ crystal

A method for the simultaneous measurement of the stimulated emission cross section and fluorescence lifetime by studying the relation between laser parameters and the laser relaxation oscillation frequency is discussed. The stimulated emission cross section for the /sup 4/F/sub 3/2/-/sup 4/I/sub 13/2/ transition of Nd/sup 3+/ ion in YAP crystal was measured to be (22+or-1)*10/sup -20/ cm/sup 2/. >

Laser action of Nd:YAlO3 at 1300 nm

From our measured value of the stimulated emission cross section for 4F3/2–4I13/2 transition of Nd3+ ion in YAlO3 crystal as well as the results of continuous wave (cw) and pulsed 1341.4 nm Nd:YAP lasers, it can be seen that Nd:YAP is an excellent 1300 nm laser crystal. In our laboratory cw output power of 195.8 W at 1341.4 nm with an overall efficiency of 1.43% and pulsed output energy of 5.1 J at 1341.4 nm with an overall efficiency of 2.02% have been achieved by using this kind of crystal.

The study of 1341.4 nm Nd:YAlO3 laser intracavity frequency doubling by LiB3O5

Abstract The study of 1341.4 nm Nd:YAlO 3 laser intracavity frequency doubling by nonlinear optical crystal LiB 3 O 5 is reported in this paper. Based on the calculation and analysis on the beam parameter inside the cavity, a 1.2 W 670 nm output power was achieved at an average pumping electrical power of 1664 W.

Measurement of refractive indices and thermal refractive-index coefficients of 7.5-mol.% Nb:KTiOPO4 crystal.

The principal refractive indices and the thermal refractive-index coefficients of 7.5-mol.% Nb:KTiOPO(4) crystal were measured by autocollimation for wavelengths of 0.53975, 0.6328, 1.0795, and 1.3414 microm from room temperature to 143 degrees C. The Sellmeier equations at room temperature were obtained and used to calculate the optimal phase-matched angles for 1.0642 and 1.0795 microm. The calculated and experimental values are in good agreement.

Twice sum‐frequency mixing of a dual‐wavelength Nd:YALO3 laser to get 413.7‐nm violet coherent radiation in LiIO3 crystal

A new method to obtain 413.7‐nm violet coherent radiation by second‐order sum‐frequency mixing of the outputs (1341.4 and 1079.5 nm) of a double‐wavelength Nd:YALO3 (Nd:YAP) laser in two LiIO3 crystals is reported. First, a 598.1‐nm orange coherent radiation is obtained by sum‐frequency mixing (SFM) of 1341.4‐ and 1079.5‐nm radiations in a LiIO3 crystal, and then the 598.1‐ and 1341.4‐nm radiations are mixed again in a second LiIO3 crystal to get 413.7‐nm radiation. The phase‐matching angles are obtained for both SFM processes. The experimental results agree well with calculated results.