Research On All-solid-state Pulsed Laser Based On Perovskite Saturable Absorbe

With the development of laser technology,yttrium-doped yttrium vanadate（Nd:YVO₄）crystal all-solid-state lasers pumped by semiconductor lasers have attracted wide attention because of their advantages of light weight,stable performance,long life and good beam quality.Saturable absorbers are the core components in all-solid-state lasers,and perovskite materials are widely used in lasers because of their excellent optical properties.On the one hand,the stability and nonlinear saturation characteristics of perovskite materials are improved by dripping graphene oxide on the surface of perovskite materials,and the output characteristics of perovskite materials in the passive Q-switched state of Nd:YVO₄ lasers are studied,and the output of the composite is narrower than that of perovskite films.On the other hand,the preparation of perovskite nanopillars was realized by using anodized aluminum template,and its output characteristics in the passive mode-locked state of Nd:YVO₄ laser were studied.Compared to the perovskites in the thin-film state,the nanopillar perovskites achieve further compression of the pulses.The specific work content of the thesis is as follows:（1）Perovskite films（CH₃NH₃Pb I₃）,graphene oxide（GO）and graphene oxide/perovskite composites（GO&CH₃NH₃Pb I₃）saturable absorbers（SA）were prepared by spin coating,and perovskite films（CH₃NH₃Pb I₃）and perovskite nanocolumn arrays（CH₃NH₃Pb I₃ nanoarray）saturated absorbers were prepared by physical vapor precipitation（PVD）and self-assembly template methods,respectively.The saturable absorbers were characterized by scanning electron microscopy,X-ray diffraction and Raman spectroscopy.The nonlinear transport characteristics of saturable absorbers were measured by Z-scan and other related techniques,and the results showed that these saturable absorbers had good saturable absorption characteristics.（2）A linear all-solid-state continuous laser with a resonant cavity length of 25 mm was constructed.CH₃NH₃Pb I₃-SA and GO&CH₃NH₃Pb I₃-SA were inserted into the resonator cavity to achieve passive Q-switched,and the output pulse waveform of the laser was recorded and analyzed.In the case of pumping power of 6.5 W,the passive Q-switched laser based on CH₃NH₃Pb I₃-SA obtained a Q-switched pulse with a minimum duration of 440 ns and a pulse repetition rate of 746 k Hz.With GO&CH₃NH₃Pb I₃-SA as the passive Q-switched device at the same pumping power,a Q-switched pulse with a minimum duration of 340 ns and a pulse repetition rate of 177.3 k Hz was obtained.（3）The W-type all-solid-state continuous laser was built,and the CH₃NH₃Pb I₃-SA and CH₃NH₃Pb I₃ nanoarray-SA were inserted into the resonant cavity of the 1064 nm all-solid-state laser as passive mode-locked devices to achieve passive mode-locked,and the output pulse waveform of the laser was recorded and analyzed.The CH₃NH₃Pb I₃-SA was inserted into the resonant cavity of the 1064 nm all-solid-state laser,and a mode-locked pulse with a pulse width of 900 ps and a repetition rate of 87 MHz was obtained under the absorbed pump power of 5.4 W.At the same absorbed pump power,a 1064 nm all-solid-state passive mode-locked laser system based on CH₃NH₃Pb I₃ nanoarray-SA obtained mode-locked pulses with a pulse width of 30 ps and a repetition rate of 87.3 MHz.