| 题名 | 钙钛矿球状微腔内高品质单模纳米激光研究 |
| 作者 | 唐冰 |
| 文献子类 | 硕士 |
| 导师 | 姜雄伟 |
| 关键词 | 单模激光，球形微腔，钙钛矿，单光子泵浦，双光子泵浦 Single-Mode Lasing, Spherical Microcavity, Perovskite, Single-Photon Excitation, Two-Photon Excitaiton |
| 其他题名 | High Quality Single-Mode Lasing in Perovskite Spherical Microcavities |
| 英文摘要 | 光学微腔作为波长量级的光学谐振腔，可实现对腔内自发辐射和受激辐射的调控。ZnO、GaN、InP等半导体纳米结构可同时作为光学微腔及增益介质使用研发微纳激光器，在光学集成、光通信及激光显示等领域具有广阔应用前景。然而，受微腔品质因子、材料增益及自发辐射耦合效率限制，目前报道的微腔输出模式基本呈现多模结构，激光单色性δλ差，激光品质因子Q偏低，激光阈值PTh较高。因此，发掘新型高增益半导体纳米材料、创新设计及制备新型高效微腔结构是实现微腔中高品质单模激光输出的关键。本文以全无机钙钛矿CsPbX3（X= Cl, Br, I）微腔为研究方向，基于CVD制备的高质量球形CsPbX3钙钛矿微腔，实现了高品质、高单色性、低阈值单模激光的宽带、可调谐输出，理论与实验相结合系统研究了各种因素对球形CsPbX3钙钛矿微腔中单模激光性能的影响，具体研究内容如下： 1）形状规则、表面光滑、尺寸可调高质量CsPbX3球状微腔的可控制备。本文基于自主搭建的真空CVD系统，创新实现了~1-10 μm球形CsPbX3钙钛矿微腔的可控制备。系统研究了球形钙钛矿样品制备过程中，反应温度（400-650℃）、基片位置（4-12 cm）、反应时间（30-60 min）、蒸发源比例 （1:1，2:1，3:1）及载气速率（1.4-2.4 L/h）对所得样品形貌及尺寸的影响，得到球形样品最佳制备条件为：反应温度~600℃；挥发源比例PbI2：CsI=2:1，硅片位置8 cm；反应时间30-40 min；载气速率2.0 L/h，其中反应时间、载气速率对样品分散性影响较大，几乎不影响样品形貌，而反应温度、生长位置及蒸发源比例对样品形貌影响较大。 2）CsPbX3钙钛矿球状微腔单光子泵浦高质量单模激光发射研究。通过显微荧光系统研究了钙钛矿微球中的光发射性质，400 nm飞秒光泵浦下在单个CsPbBr3钙钛矿球状微腔中实现了高品质（Q~6100）、高单色性（δλ~0.09 nm）、低阈值（PTh~0.42 μJ/cm2）单模激光输出。随后，系统研究了球状微腔尺寸、温度、泵浦源脉宽对单模激光输出性能的影响，对单模激光的寿命，输出稳定性进行了表征。通过调节CsPbX3钙钛矿卤素配比，首次实现了覆盖可见光区高品质单模激光的宽带、可调谐输出。 3）CsPbBr3钙钛矿球状微腔双光子泵浦超高品质单模激光发射研究。首先通过800 nm泵浦光特定激发单个CsPbBr3球形腔，观察到了双光子泵浦荧光发射现象，证实了CsPbBr3具有双光子吸收特性。基于CsPbBr3纳米结构优异的双光子吸收特性，800 nm飞秒光泵浦下在单个CsPbBr3钙钛矿球状微腔中实现了超高品质（Q~1.5×104）、高单色性（δλ~0.037 nm）、低阈值（PTh~203.7 μJ/cm2）单模激光输出，通过尺寸调节实现了小范围（533-543 nm）超高品质（Q>104）单模激光调谐输出。基于角分辨荧光光谱表征了CsPbBr3球形腔独特的角发射特性，由于球状腔性质规则、表面光滑在-30°-30°各角度得到了性质一致的单模激光输出。最后，通过低温实验进一步提高了单模激光的单色性（δλ~0.0177 nm），其激光品质因子Q高达~3×104，发现了其随温度变化异常的波长移动行为。 综上，本文通过理论与实验系统研究了球形CsPbX3钙钛矿微腔中单模激光的发射特性，在CsPbX3球状腔内首次实现了覆盖可见光区高品质、高单色性、低阈值单模激光的宽带、可调谐输出。基于CsPbBr3的优异双光子吸收特性，通过双光子泵浦实现了超高品质单模激光输出，极大提高了单模激光的单色性。本工作为高品质单模激光的宽带、可调谐输出奠定了基础，为新型高品质半导体微腔的设计和制备提供了新的思路。; Microcavity as optical resonator at nanoscale can modulate spontaneous and stimulated emission. Nanolasers can be developed using the micro/nanostructures of ZnO, GaN, InP both as microcavity and gain medium, which has widely applications in photonic integration, optical communication and laser display. However, constrained by microcavity quality, gain medium and spontaneous emission coupling efficiency, the realization of single-mode lasing is still a great challenge, most reported microcavity lasing just exhibit multimode structure, poor monochromaticity, low lasing quality factor, high lasing threshold. Therefore, developing new semiconductor nanostructures with high optical gain and innovatively designing and preparing new microcavity structure is the key factor to realize high quality single-mode laser. In this paper, high quality CsPbX3 (X= Cl, Br, I) perovskite microspheres were prepared by chemical vapor deposition, then widely tunable single-mode lasers covering the visible region with high quality factor, narrow lasing linewidth, low lasing threshold have been made in CsPbX3 spherical microcavity. Also the effects of microcavity size, pulse duration, experimental temperature on the performance of single-mode lasing have been systematically studied practically and theoretically. The detailed information is listed out as follows: 1) The controllable preparation of CsPbX3 spherical microcavity with regularly structure, smooth surface and tunable size. The controllable preparation of ~1-10 μm spherical CsPbX3 perovskite microcavity has been innovatively realized in home-built chemical vapor deposition system. The effects of reaction temperature (400-650℃), silicon position (4-12 cm), reaction time (30-60 min), the ratio of source material (1:1, 2:1, 3:1) and gas flowing rate (1.4-2.4 L/h) on the morphology and size of as-synthesize samples have been systematically studied. We find that the reaction time and gas flowing rate have less influence on morphology, but determine their density; the shape is mainly determined by reaction temperature, silicon position and source ratio; thus the best condition for spherical nanostructure is as follows: reaction temperature ~600℃, silicon position ~8 cm, reaction time 30-40 min, the ratio of source material ~2:1 and gas flowing rate 2.0 L/h 2) Single-photon excitation single-mode lasing obtained in CsPbX3 perovskite spherical microcavity. The photoemission properties of perovskite microspheres have been studied by micro-photoluminescence system, high quality (Q~6100) single-mode lasing with high monochromaticity (δλ~0.09 nm), low lasing threshold (PTh~0.42 μJ/cm2) was realized in CsPbBr3 spherical microcavity under 400 nm femosecond laser excitaion. Also the influence of microcavity size, experimental temperature, pulse duration on the property of single-mode lasing and the lifetime and output stability of single-mode lasing have been characterized. The widely tunable single-mode lasing covering the visible region was first realized through halide substitution of CsPbX3. 3) Two-photon excitation single-mode lasing with ultra-high quality factor achieved in CsPbX3 perovskite spherical microcavity. Two-photon excited photoluminescence has been observed in CsPbBr3 microcavity under 800 nm femtosecond excitation, demonstrating the two-photon absorption inside the sphere. Based on its superior two-photon absorption coefficient, ultra-high quality (Q~1.5×104) single-mode lasing with much narrower linewidth (δλ~0.037 nm), low lasing threshold (PTh~203.7 μJ/cm2) has been made in CsPbBr3 spherical microcavity. Also the tunability of ultra-high quality (Q>104) single-mode lasing from 533-543 nm has been verified through cavity size modulation. Due to the regularly structure and smooth surface of spherical microcavity, single-mode lasing with similar property has been recorded at any angle between -30° and 30° by angle-resolved photoluminescence. Much higher quality single-mode lasing (Q~3×104) with narrower lasing linewidth (δλ~0.0177 nm) has been demonstrated at low temperature, and its abnormal shift of resonator wavelength has been recorded. Thus, the property of single lasing in CsPbX3 has been studied experimentally and theoretically, high quality, narrow linewidth, low threshold single-mode lasing covering the whole visible region has been first realized in CsPbX3 perovskite microcavity. Ultra-high quality single-mode lasing with much narrower linewidth has been demonstrated in CsPbBr3 spherical microcavity due to its superior two-absorption property. This work provide solid foundation for high quality single-mode lasing with widely tunability, and new path to design and synthesize high quality semiconductor microcavity. |
| 学科主题 | 材料学 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/31030]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 唐冰. 钙钛矿球状微腔内高品质单模纳米激光研究[D]. |
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