基于金属纳米颗粒的局域表面等离子体共振效应的随机光纤激光的研究

The nondirectional and high threshold characters of the traditional random laser (RL) systems have largely limited their application. The effect of one-dimensional confinement on the lasing properties of a classical RL system has obtained bringing about the birth of random fiber lasers (RFLs) with low threshold and directionality. Gold (Au) nanoparticles (NPs) as scattering centers based on the localized surface plasmon resonance (LSPR) will induces selective enhancement of the photoluminescence spectrum, which will decrease the threshold of random laser in the random system. In this project, we combine the effects of one-dimensional confinement on the lasing properties of a classical RL system and LSPR of Au NPs to fabricate Au NPs doped polymer optical fiber with gain medium. The effect of LSPR of Au NPs on the one-dimensional confinement of the fiber will be researched. The overlap between of the LSPR of the Au NPs and the photoluminescence spectrum will be analyzed how to influence the threshold and emission wavelength of the RL. Meanwhile, the stability of the random fiber laser also is researched. We exploit the low spatial coherence of specifically designed random fiber lasers as light source to demonstrate speckle-free full-field imaging in the setting of intense optical scattering.

传统随机激光由于无方向性和高阈值特性影响它们的应用。人们利用光纤一维波导效应得到有一定方向性及低阈值的随机激光。金属纳米颗粒的局域表面等离子体共振效应对荧光分子的荧光有选择性增强效应，从而在随机系统中金纳米颗粒可以降低随机激光的阈值。本项目结合一维光纤对随机激光的束缚作用和金纳米颗粒的局域表面等离子体共振效应制作金纳米颗粒掺杂的增益聚合物光纤。研究金纳米颗粒在一维光纤下的局域表面等离子体共振效应。分别研究在大块体系和一维光纤体系中金纳米颗粒的局域表面等离子体共振效应与荧光分子的发射谱重叠度对随机激光的阈值及其随机激光波长的影响。研究这种随机光纤激光的光谱稳定性。由于随机激光的低空间相干性，我们用这种随机光纤激光作为光源，研究其对散斑抑制的影响，开展随机光纤激光成像的研究。

随机激光是一种非传统激光，不需要反射镜作为反馈机制，它利用散射介质的多重散射反馈作为反馈机制，在无序的增益介质中发生受激辐射现象，从而得到激光出射。但是传统随机激光由于无方向性和高阈值特性影响它们的应用。人们利用光纤一维波导效应得到有一定方向性及低阈值的随机激光。金属纳米颗粒的局域表面等离子体共振效应（LSPR）对荧光分子的荧光有选择性增强效应，从而在随机系统中金纳米颗粒可以降低随机激光的阈值。本项目结合一维光纤对随机激光的束缚作用和金纳米颗粒的局域表面等离子体共振效应制作金纳米颗粒掺杂的增益聚合物光纤。研究金纳米颗粒在一维光纤下的局域表面等离子体共振效应。首先，我们利用特氟龙法制作不同类型的无序增益聚合物光纤：无纳米颗粒掺杂的光纤；介质纳米掺杂的光纤；超顺磁性纳米颗粒掺的光纤；金属纳米颗粒掺杂的光纤；其次，研究金属的LSPR效应对随机激光的波长及阈值的调控，同时研究掺杂光纤的无序度对随机激光波长的调控，掺杂光纤的取向调控随机激光的偏振态；最后研究微纳激光材料近场散射及分子聚集对随机激光的影响。本项目研究不仅丰富了随机激光的科学内涵，而且为它在物理光学、和化学材料等领域上的应用提供科学依据。