Key Laboratory of Optical Fiber Sensing and Communications (Education Ministry of China), University of Electronic Science and Technology of China , Chengdu 610054, China.
Fang Lu Mesoscopic Optics and Quantum Electronics Laboratory, University of California , Los Angeles, California 90095, United States.
Nano Lett. 2017 Aug 9;17(8):4996-5002. doi: 10.1021/acs.nanolett.7b02176. Epub 2017 Jul 18.
Chemical sensing is one of the most important applications of nanoscience, whose ultimate aim is to seek higher sensitivity. In recent years, graphene with intriguing quantum properties has spurred dramatic advances ranging from materials science to optoelectronics and mechanics, showing its potential to realize individual molecule solid-state sensors. However, for optical sensing the single atom thickness of graphene greatly limits the light-graphene interactions, bottlenecking their performances. Here we demonstrate a novel approach based on the forward phase-matched Brillouin optomechanics in a graphene inner-deposited high Q (>2 × 10) microfluidic resonator, expanding the "electron-photon" interaction in conventional graphene optical devices to the "electron-phonon-photon" process. The molecular adsorption induced surface elastic modulation in graphene enables the Brillouin optomechanical modes (mechanical Q ≈ 43,670) extremely sensitive (200 kHz/ppm) in ammonia gas detection, achieving a noise equivalent detection limit down to 1 ppb and an unprecedented dynamic range over five orders-of-magnitude with fast response. This work provides a new platform for the researches of graphene-based optomechanics, nanophotonics, and optical sensing.
化学传感是纳米科学最重要的应用之一，其最终目标是寻求更高的灵敏度。近年来，具有奇异量子特性的石墨烯极大地推动了从材料科学到光电子学和力学的发展，显示出其实现单个分子固态传感器的潜力。然而，对于光学传感来说，石墨烯的单原子厚度极大地限制了光与石墨烯的相互作用，限制了其性能。在这里，我们基于石墨烯内沉积高 Q（>2×10）微流腔中的前向相位匹配布里渊光机械学，展示了一种新的方法，将传统石墨烯光器件中的“电子-光子”相互作用扩展到“电子-声子-光子”过程。石墨烯中分子吸附引起的表面弹性调制使布里渊光机械模式（机械 Q ≈ 43670）在氨气检测中具有极高的灵敏度（200 kHz/ppm），实现了低至 1 ppb 的噪声等效检测限和前所未有的五个数量级的动态范围，响应速度快。这项工作为基于石墨烯的光机械学、纳米光子学和光学传感研究提供了一个新的平台。
