介电电泳控制的光流控体系中有机随机激光发射研究

Random lasing is a relatively new discovery in the lasing emission theory. It has attracted much attention due to its unique properties and wide applications. However, a random medium would result in unpredictable and uncontrolled lasing properties. Until now, in whether theoretical or experimental study, there is seldom report for a keen understanding of what factors impact the various properties of random lasing emission. This project will propose an exciting new random lasing system- - Dielectrophoretically controlled optofluidic platforms, which will create a dynamically reconfigurable and actively controlled random lasing mode. By changing the applied voltage and frequency, particles can be focused to, or repelled from pre-determined locations within a microfluidic channel, and concequently, the random lasing mode will be controlled. With fluid suspended scattering particles and dielectrophoretic control of inter-particle spacing, distribution and cavity topology, the random lasing emission characteristics will be studied in detail. We also investigate the dependence of random lasing emission on dielectrophoretically controlled particle-shape, dielectric constant, surface chemistry and scatterer density, finally explore the utility of this new, flexibly reconfigurable microlaser platform. Success in this project will provide a new technology for low-cost reconfigurable organic random lasers, and lay the foundation for self-developed organic random lasers in China.

随机激光发射是激光发射原理中一个全新的概念，以其独特的发光原理和广阔的应用前景受到了众多国内外学者的关注。然而，目前随机激光无论是在理论研究还是实验上都缺乏对随机性的定量描述，输出模式的不可控性和相对较高的激光阈值，仍是随机激光发展亟待解决的问题。本项目针对目前随机激光研究中输出模式不可控的难点，提出了一种全新的随机激光体系- - 介电电泳控制的光流控体系。在该体系中，采用非均匀电场极化分散在光流控体系中的散射粒子，同时通过调控外加电压、频率、流速等外在参数对散射粒子进行分散、富集和定位，从而达到对随机激光光谱输出模式的调节。同时，通过优化散射粒子表面环境，获得低阈值的随机激光发射。确定随机激光输出模式与散射体间的相互作用，实现随机激光模式的最有效控制，成功制备出新型、灵活、可控的微随机激光器。此项研究的开展将为开发输出模式可控的有机随机激光器提供新的思路，为我国自主研发有机随机激光器奠定基础

随机激光发射是激光发射原理中一个全新的概念，以其独特的发光原理和特殊的物理机制受到了众多国内外学者的关注。如何选择合理有效的散射体系，更有效地改进其光谱特性，降低激光输出的阈值，使之与传统激光器相媲美，是随机激光器研究中的关键问题之一。本项目通过改变散射介质的材料、形貌、大小和浓度详细研究了随机激光的物理机制，深入探讨了散射体对随机激光的影响，成功制备了低阈值的随机激光器件。研究发现，长程有序的晶体结构可以提供有效的正反馈，是降低激光阈值的有效途径；随机激光的光谱和阈值明显依赖于散射介质，引入金属银纳米颗粒作为散射介质时，通过有效激发金属表面等离子体参与到随机激光的发射中，可以有效地降低随机激光的阈值；介电电泳控制的光流体系，通过改变电压、频率等电泳参数可以有效地控制介质的散射效应。本项目的成功开展，有助于了解随机激光的机理，有助于拓展随机激光的应用范围。