A random Q-switched fiber laser.

Jianqiu Xu,Yulong Tang

doi:10.1038/srep09338

Abstract

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.

Highlights

IntroductionDisordered optics, which is the subject of light transport through non-uniform media, has attracted considerable interest and has numerous potential applications such as imaging, remote sensing, random lasers, and solar energy[1]
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
The laser system primarily consists of one piece of an ultra-high numerical aperture (UHNA) passive fiber that is fusion-spliced with one www.nature.com/scientificreports piece of a Tm31 gain fiber

Summary

Introduction

Disordered optics, which is the subject of light transport through non-uniform media, has attracted considerable interest and has numerous potential applications such as imaging, remote sensing, random lasers, and solar energy[1]. Among these areas, random lasers are especially important because of their unique properties and rich underlying laser physics, which are of fundamental scientific interest. Standard regular lasers, which have definite cavity modes, can be Q-switched with a conventional modulator to produce giant energy pulses and high peak power. The random Q-switched fiber laser (RQFL) outputs stored energy over a short time interval, which greatly improves the emission brightness (peak power). Immediate intriguing applications of high-power random lasers include speckle-free imaging[24] and full-field optical coherence tomography[25]

Methods

Results

Discussion

Conclusion