| Diode pumped solid stated short pulse lasers possess significant application value. The key of realizing short pulse laser oscillation is choosing appropriate gain medium and modulate component. Nd doped vanadates and garnet are two kinds of important laser gain medium. The large absorption and emission cross sections and short upper energy level of Nd doped vanadates are in favor of high efficient continuous wave laser operation. The actively Q-switching technique can be utilized for short pulse generation. By changing components or selecting oriention, Nd doped vanadates can be used to construct passively Q-switched microchip lasers for short pulse laser generation. The stimulated emission cross sections of 4F3/2â†'4I13/2,4F3/2â†'4I9/2 are samller than that of 4F3/2â†'4I11/2 transition, so the corresponding emission wavelengths are excellent candidates for short pulse laser oscillation. Limited by narrow saturable absorption band of traditional saturable absorber Cr4+:YAG, V3+:YAG, we tried new two dimensional broadband saturable absorption crystal (graphene, TMD) for short pulse laser experiment.The dissertation is outlined as followed:Sub-nanosecond passively Q-switched microchip lasers based on Nd:YVO4, Nd:GdVO4 single crystals and Nd:GdxY1-xVO4 (x=0,0.18,0.42,0.51,0.64, and 1.), Nd:Lu0.61Gd0.39VO4 mixed crystals and Cr4+:YAG were reported. The shortest pulse width of 693,420,588,646 ps were realized, corresponding to peak power of 30,28, 48,13.5 kW, respectively.For Nd:LaxY1-xVO4 (x=0.11) and Nd:LaxLu1-xVO4 (x=0.05) crystals, the 4F3/2â†'4II3/2 transition property was investigated. For acousto-optic (AO) Q-switched laser operation, the shortest pulse width, highest peak power and maximum pulse energy came from the a-cut samples, which were 13 ns,2.69 kW and 35μJ,44 ns, 273 W,12μJ respectively. For passively Q-switched laser operation, the shortest pulse width, highest peak power and maximum pulse energy reached 41 ns,199 W, 8.2μJ, respectively.Graphene saturable absorber (SA) was used as the passive Q-switcher of a 0.9μm solid state laser. When the laser medium is a Nd:La0.11Y0.89VO4 crystal, at an absorbed pump power of 7.62 W, the maximum average output power, largest pulse energy, and minimum pulse width was 0.62 W,240 kHz, and 84 ns, respectively. When the laser medium is a Nd:YAG crystal, at an absorbed pump power of 9.5 W, the maximum average output power of 0.9 W, corresponding to an optical to optical conversion efficiency of 9.5%. The pulse repetition frequency and the pulse width are 225 kHz, 162 ns, respectively, resulting pulse energy of 4μJ and a peak power of 24.7 W.Two-dimensional (2D) transition metal dichalcogenides are attracting increased attention because of their excellent electronic and optical properties. Inspired by the natural weathering exfoliation of seaside rocks, we proposed a "chemical weathering" concept for fabricating atom-thick 2D materials from their bulk counterparts. We experimentally demonstrated that chemical weathering-assisted exfoliation mechanism was a simple and efficient method of preparing atom-thick MoS2 and WS2 monolayers. These monolayers are difficult to prepare using other approaches. The as-prepared MoS2 and WS2 monolayers exhibited excellent saturable absorption and mode-locking properties in all-solid-state lasers because of intermediate states resulting from S-vacancy defects. The obtained passively Q-switched laser operation with 60 ns pulse width and ultrafast mode locking with 8.6 ps pulse width were promising for all-solid-state laser application.LD pumped Nd:LuGdAG eye-safe single, dual-wavelength lasers were reported. With a plano-concave resonator, a maximum single, dual-wavlength continuous wave (CW) output power of 1.05,1.00 W were obtained under an absorbed pump power of 8.52 W, corresponding to optical to optical conversion efficiency of 12.3%,11.7% and slope efficiency of 14.5%,13.6%. With a 5-7 layer graphene as the saturable absorber, the passively Q-switched 1444 nm operation was achieved. The maximum average output power, shortest pulse width, and highest repetition frequency were 0.29 W,324 ns,64 kHz, respectively.Optical bistability was realized in a passively Q-switched Nd:Lu0.14Gd0.86VO4 microchip laser. The bistable operation range for the incident pump power was 5.9 to 7.3 W, and the jump output power at the turning point was 0.24 W. By using a four-level laser model with a saturable absorber and Fabry-Perot cavity, the calculated results agreed well with the experimental data.A new method was used to direct generate Ince-Gaussian modes from pulsed solid state microchip laser. By moving a circular aperture horizontally, the gain size in the laser medium was adjusted and different Ince-Gaussian laser modes were obtained successively. The output laser possesses stable pulse duration of 500～600 ps, at the same time the repetition frequency varies between 7 and 16 kHz. To our knowledge, this is the first time that Ince-Gaussian modes were obtained in sub-nanosecond laser domain, which will be helpful for making large energy, high peak power devices. |
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