Hu Han-Wen, Haider Golam, Liao Yu-Ming, Roy Pradip Kumar, Lin Hung-I, Lin Shih-Yao, Chen Yang-Fang
Department of Physics, National Taiwan University, Taipei 10617, Taiwan.
Academy of Sciences of the Czech Republic, J. Heyrovský Institute of Physical Chemistry, Prague 8, Czechia.
ACS Omega. 2020 Jul 21;5(30):18551-18556. doi: 10.1021/acsomega.9b04094. eCollection 2020 Aug 4.
Total internal reflection is one of the most important phenomena when a propagated wave strikes a medium boundary, which possesses a wide range of applications spanning from optical communication to a fluorescence microscope. It has also been widely used to demonstrate conventional laser actions with resonant cavities. Recently, cavity-free stimulated emission of radiation has attracted great attention in disordered media because of several exciting physical phenomena, ranging from Anderson localization of light to speckle-free imaging. However, unlike conventional laser systems, the total internal reflection has never been implemented in the study of laser actions derived from randomly distributed media. Herein, we demonstrate an ultra-low threshold cavity-free laser system using air bubbles as scattering centers in which the total internal reflection from the surface of air bubbles can greatly reduce the leakage of the scattered beam energy and then enhance light amplification within a coherent closed loop. Our approach provides an excellent alternative for the manipulation of optical energy flow to achieve ultra-low threshold cavity-free laser systems, which should be very useful for the development of high performance optoelectronic devices.
当传播的波撞击介质边界时，全内反射是最重要的现象之一，它在从光通信到荧光显微镜等广泛的应用中都有涉及。它也被广泛用于通过谐振腔来演示传统的激光作用。最近，由于从光的安德森局域化到无散斑成像等多种令人兴奋的物理现象，无腔受激辐射在无序介质中引起了极大关注。然而，与传统激光系统不同，全内反射从未在源自随机分布介质的激光作用研究中得到应用。在此，我们展示了一种以气泡作为散射中心的超低阈值无腔激光系统，其中气泡表面的全内反射可以大大减少散射光束能量的泄漏，进而增强相干闭环内的光放大。我们的方法为操纵光能量流以实现超低阈值无腔激光系统提供了一个绝佳的选择，这对于高性能光电器件的开发应该非常有用。
