近日，国防科技大学罗晖、肖光宗，湖南师范大学景辉等研制了具有主动悬浮光力学的非线性多频声子激光器。2023年1月19日，国际知名学术期刊《自然—物理学》发表了这一成果。
本文报道了一种基于耗散耦合的微球非线性多频声子激光器。Yb3+掺杂体系提供的有源增益起着关键作用。与无源器件相比，基模声子激射振幅提高了3个数量级。此外，非线性机械谐波可以自发地出现在激光阈值以上。
此外，研究人员还观察到基模及其谐波的声子相干关联。他们的工作推动了悬浮光力学领域的发展，使设计典型微观物体的集体运动特性变得可行。
据介绍，声子激光器利用声子的相干放大，是一种探索非线性声子、成像纳米材料结构和操作声子器件的手段。最近，通过悬浮在光镊中的纳米球，证明了色散光机耦合控制的声子激光器。这种悬浮光机械装置，在高真空环境下噪音最小，可以在没有任何内部离散能量水平的情况下灵活控制大质量物体。然而，在悬浮的微尺度物体上实现声子激光具有很大的挑战性，因为悬浮的微尺度物体的光散射损失要比纳米尺度物体大得多。
附：英文原文
Title: Nonlinear multi-frequency phonon lasers with active levitated optomechanics
Author: Kuang, Tengfang, Huang, Ran, Xiong, Wei, Zuo, Yunlan, Han, Xiang, Nori, Franco, Qiu, Cheng-Wei, Luo, Hui, Jing, Hui, Xiao, Guangzong
Issue&Volume: 2023-01-19
Abstract: Phonon lasers, which exploit coherent amplifications of phonons, are a means to explore nonlinear phononics, image nanomaterial structures and operate phononic devices. Recently, a phonon laser governed by dispersive optomechanical coupling has been demonstrated by levitating a nanosphere in an optical tweezer. Such levitated optomechanical devices, with minimal noise in high vacuum, can allow flexible control of large-mass objects without any internal discrete energy levels. However, it is challenging to achieve phonon lasing with levitated microscale objects because optical scattering losses are much larger than at the nanoscale. Here we report a nonlinear multi-frequency phonon laser with a micro-size sphere, which is governed by dissipative coupling. The active gain provided by a Yb3+-doped system plays a key role. It achieves three orders of magnitude for the amplitude of the fundamental-mode phonon lasing, compared with the passive device. In addition, nonlinear mechanical harmonics can emerge spontaneously above the lasing threshold. Furthermore, we observe coherent correlations of phonons for both the fundamental mode and its harmonics. Our work drives the field of levitated optomechanics into a regime where it becomes feasible to engineer collective motional properties of typical micro-size objects.
DOI: 10.1038/s41567-022-01857-9
Source: https://www.nature.com/articles/s41567-022-01857-9