近日，北京大学的马仁敏及其研究团队取得一项新进展。经过不懈努力，他们研制出具有原子尺度场定位的奇异介质纳米激光器。相关研究成果已于2024年7月17日在国际权威学术期刊《自然》上发表。

该研究团队提出并演示了奇异介质纳米激光器，其模体积打破了光学衍射极限。从麦克斯韦方程出发，研究人员发现电介质领结纳米天线中的电场奇点是由动量散度引起的。奇异介质纳米激光器是通过在扭曲晶格纳米腔的中心集成一个介质领结纳米天线来构建的。这种协同集成超越了衍射极限，使得单一介质纳米激光器实现约0.0005 λ (λ，自由空间波长)的超小型模体积，并且在1纳米尺度上具有极小的特征尺寸。

为了制造所需的具有单纳米间隙的介电领结纳米天线，研究人员开发了两步工艺，包括蚀刻和原子沉积。这项研究展示了在激光设备中实现原子尺度场定位的能力，为超精确测量、超分辨率成像、超高效计算和通信以及在极端光场定位领域探索光-物质相互作用铺平了道路。

据悉，将光场压缩到原子尺度，为直接观察单个分子开辟了可能性，为物理和生命科学提供了创新的成像和研究工具。然而，衍射极限对光场可以被压缩的程度施加了一个基本的限制，这是基于可实现的光子动量。与介电结构相比，等离子体通过将光场与金属中自由电子的振荡耦合，提供了优越的场约束。然而，等离子体存在固有的欧姆损耗，导致热的产生、功耗的增加和等离子体器件相干时间的限制。

附：英文原文

Title: Singular dielectric nanolaser with atomic-scale field localization

Author: Ouyang, Yun-Hao, Luan, Hong-Yi, Zhao, Zi-Wei, Mao, Wen-Zhi, Ma, Ren-Min

Issue&Volume: 2024-07-17

Abstract: Compressing the optical field to the atomic scale opens up possibilities for directly observing individual molecules, offering innovative imaging and research tools for both physical and life sciences. However, the diffraction limit imposes a fundamental constraint on how much the optical field can be compressed, based on the achievable photon momentum. In contrast to dielectric structures, plasmonics offer superior field confinement by coupling the light field with the oscillations of free electrons in metals. Nevertheless, plasmonics suffer from inherent ohmic loss, leading to heat generation, increased power consumption and limitations on the coherence time of plasmonic devices. Here we propose and demonstrate singular dielectric nanolasers showing a mode volume that breaks the optical diffraction limit. Derived from Maxwell’s equations, we discover that the electric-field singularity sustained in a dielectric bowtie nanoantenna originates from divergence of momentum. The singular dielectric nanolaser is constructed by integrating a dielectric bowtie nanoantenna into the centre of a twisted lattice nanocavity. The synergistic integration surpasses the diffraction limit, enabling the singular dielectric nanolaser to achieve an ultrasmall mode volume of about 0.0005 λ³ (λ, free-space wavelength), along with an exceptionally small feature size at the 1-nanometre scale. To fabricate the required dielectric bowtie nanoantenna with a single-nanometre gap, we develop a two-step process involving etching and atomic deposition. Our research showcases the ability to achieve atomic-scale field localization in laser devices, paving the way for ultra-precise measurements, super-resolution imaging, ultra-efficient computing and communication, and the exploration of light–matter interactions within the realm of extreme optical field localization.

DOI: 10.1038/s41586-024-07674-9

Source: https://www.nature.com/articles/s41586-024-07674-9