Shixia Li

1.1 MW peak power in doubly QML composite Nd:YVO 4 /Nd:YVO 4 /Nd:YVO 4 /KTP sub-nanosecond green laser with EO and Bi-GaAs

By simultaneously employing electro-optic (EO) modulator and Bi-doped GaAs, dual-loss-modulated Q-switched and mode-locked (QML) multi-segment composite Nd:YVO4/Nd:YVO4/Nd:YVO4/KTP sub-nanosecond green laser is demonstrated with low repetition rate and high peak power. When the incident pump power is up to 6.93 W, only one mode-locking pulse underneath a Q-switching envelope is generated with sub-nanosecond pulse duration at one kilohertz repetition rate. An average output power of 445 mW and a pulse duration of 399 ps are obtained with the incident pump power of 11.13 W, corresponding to a peak power of 1.115 MW which is the highest one in doubly QML sub-nanosecond green laser by now. The laser characteristics are better than those obtained with EO and GaAs. The experimental results indicate that Bi-GaAs is a promising saturable absorber for dual-loss-modulated QML laser.

5.1-ps passively mode-locked Nd:LuLiF 4 laser

We report on the first investigation of a passive mode-locking Nd:LuLiF4 laser at 1047 nm with semiconductor saturable absorber mirror. The maximal average output power of 1.21 W was obtained with a slope efficiency of 10.8%, under an incident pump power of 12.6 W. The pulse duration of 5.1 ps and a spectral width of 0.45 nm were obtained with a repetition rate of 40 MHz. This corresponds to the single pulse energy of 30.3 nJ and the peak power of 5.93 kW.

Experimental and theoretical investigation on passively Q-switched laser action in c-cut Nd:MgO:LiNbO₃.

The performance of a diode-pumped c-cut Nd:MgO:LiNbO3 laser at 1093 nm was demonstrated. Under an absorbed pump power of 7.450 W, a maximum continuous wave output power of 1.570 W was obtained, corresponding to a slope efficiency of 26.0%. For passive Q-switching operation, 24 ns pulses were observed with a repetition rate of 17.1 kHz, resulting in a peak power of 1357 W. The experimental results were theoretically analyzed by a rate equation model, in which the Gaussian spatial distribution of the intracavity photon density was taken into account.

Theoretical and Experimental Study on High Peak Power Sub-Nanosecond Pulse Characteristics of Multi-Segment Composite Nd:YVO 4 Laser

By simultaneously employing electro-optic modulator and GaAs, the dual-loss-modulated Q-switched and mode-locked sub-nanosecond laser of the multi-segment composite Nd:YVO4/Nd:YVO4/Nd:YVO4 crystal was investigated for the first time. The threshold pump power for obtaining the single mode-locking sub-nanosecond pulses was 5.72 W. When the incident pump power was 8.76 W, the maximal average output power of 885 mW and the shortest pulse duration of 489 ps were generated at 1 kHz repetition rate, corresponding to the highest peak power of 1.8 MW. Compared with the conventional Nd:YVO4 crystal, the multi-segment composite one depicted better thermomechanical performance and obtained much higher peak power. Coupled rate equations are brought in to theoretically analyze the experimental results, in which a hyperbolic secant square function and the Gaussian distribution of the intracavity photon density are considered. The simulated calculations are in accordance with the experimental results.