Shi Xiaoyu, Bian Yaoxing, Tong Junhua, Liu Dahe, Zhou Jing, Wang Zhaona
Opt Express. 2020 Apr 27;28(9):13576-13585. doi: 10.1364/OE.384246.
The color and/or chromaticity controllability of random lasing is a key factor to promote practical applications of random lasers as high luminance sources for speckle-free imaging. Here, white coherent random lasing with tunable chromaticity is obtained by using broadband enhancement Au-Ag nanowires as scatterers and the resonance energy transfer process between different dyes in the capillary microfluidic channel. Red, green and blue random lasers are separately fabricated with low thresholds, benefiting from the plasmonic resonance of the nanogaps and/or nanotips with random distribution and sizes within Au-Ag nanowires and positive optical feedback provided by the capillary wall. A white random laser system is then designed through reorganizing the three random lasers. And, the chromaticity of the white random laser is flexibly tunable by adjusting pump power density. In addition, the white random laser has anisotropic spectra due to the coupling role between the lasers. This characteristic is then utilized to obtain different random lasing with different chromaticity over a broad visible range. The results may provide a basis for applying random laser in the field of high brightness illumination, biomedical imaging, and sensors.
随机激光的颜色和/或色度可控性是推动随机激光器作为无散斑成像的高亮度光源实际应用的关键因素。在此，通过使用宽带增强的金-银纳米线作为散射体以及毛细管微流控通道中不同染料之间的共振能量转移过程，获得了具有可调色度的白色相干随机激光。得益于金-银纳米线内随机分布和尺寸的纳米间隙和/或纳米尖端的等离子体共振以及毛细管壁提供的正光学反馈，分别制造出了具有低阈值的红色、绿色和蓝色随机激光器。然后通过重组这三种随机激光器设计出一个白色随机激光系统。并且，通过调节泵浦功率密度，白色随机激光的色度可灵活调谐。此外，由于激光器之间的耦合作用，白色随机激光具有各向异性光谱。利用这一特性可在较宽的可见光范围内获得不同色度的不同随机激光。这些结果可为随机激光在高亮度照明、生物医学成像和传感器领域的应用提供依据。
