Tang Yulong, Xu Jianqiu
Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China.
Sci Rep. 2015 Mar 23;5:9338. doi: 10.1038/srep09338.
Extensive studies have been performed on random lasers in which multiple-scattering feedback is used to generate coherent emission. Q-switching and mode-locking are well-known routes for achieving high peak power output in conventional lasers. However, in random lasers, the ubiquitous random cavities that are formed by multiple scattering inhibit energy storage, making Q-switching impossible. In this paper, widespread Rayleigh scattering arising from the intrinsic micro-scale refractive-index irregularities of fiber cores is used to form random cavities along the fiber. The Q-factor of the cavity is rapidly increased by stimulated Brillouin scattering just after the spontaneous emission is enhanced by random cavity resonances, resulting in random Q-switched pulses with high brightness and high peak power. This report is the first observation of high-brightness random Q-switched laser emission and is expected to stimulate new areas of scientific research and applications, including encryption, remote three-dimensional random imaging and the simulation of stellar lasing.
人们对随机激光器进行了广泛研究，其中利用多重散射反馈来产生相干发射。调Q和锁模是在传统激光器中实现高峰值功率输出的众所周知的方法。然而，在随机激光器中，由多重散射形成的普遍存在的随机腔体会抑制能量存储，使得调Q无法实现。在本文中，利用光纤芯的固有微观尺度折射率不规则性产生的广泛瑞利散射，沿着光纤形成随机腔体。在自发发射通过随机腔共振得到增强之后，受激布里渊散射迅速提高了腔体的品质因数，从而产生具有高亮度和高峰值功率的随机调Q脉冲。本报告首次观测到高亮度随机调Q激光发射，有望激发包括加密、远程三维随机成像和恒星激光模拟在内的新科研和应用领域。
