| Summary: | 碩士 === 國立中山大學 === 光電工程學系研究所 === 103 === In this thesis, the characteristics of high power solid-state pulsed laser by using topological insulator Bi2Te3 saturable absorber were investigated. First, the high yield of Bi2Te3 nanosheets were successfully fabricated by hydrothermal exfoliation, which had been certificated with X-ray diffraction, raman spectrum characterizations, energy-dispersive X-ray spectroscopy, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. All the results confirms anvantanges and feasibility of convient route for producing saturable absorber. This is beneficial to further commercial solid-state laser applications.
In addition, we demonstarted passive solid-state pulsed laser by exfoliated topological insulators Bi2Te3 and reliazed stable Q-switching operation by folded resonator in order to prevent residual pumping power. The obtained pulse energy is over than 5 μJ at 1.06 µm. This is the greatest value in TI-based solid-state laser to our best knowledgement. Finally, by virtue of improved resonator, the optimized Q-switching performances compare favorably with different coverage of saturable absorber at 1.06 µm and 1.34 µm. We have experimentally demonstrated that output power of 326 mW、pulse energy of 2.8 μJ and pulse duration of 673 ns at 1.34 µm waveband. Furthermore, we have displayed the influence of thermal effect on saturable absorber within resonator for the first time. By analysing the analogue process of beam waist and transforming the position of saturable saturaber within resonator, it will reach the higher pulse power and energy on account of contributions to more topological insulators. Moreover, we oberserved that low threshold characteristics of topological insulators as fast saturable absorber accompanied with increasing pumping power would lead to excessively high repetition rate. Above following discussion, Q-switching pulsed operation would convert into condition of continuous wave when it raised up to certain level of pumping power
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