Xu Jipeng, Mao Yuanhao, Li Zhipeng, Zuo Yunlan, Zhang Jianfa, Yang Biao, Xu Wei, Liu Ning, Deng Zhi Jiao, Chen Wei, Xia Keyu, Qiu Cheng-Wei, Zhu Zhihong, Jing Hui, Liu Ken
College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha, China.
Hunan Provincial Key Laboratory of Novel Nano-Optoelectronic Information Materials and Devices, National University of Defense Technology, Changsha, China.
Nat Nanotechnol. 2024 Oct;19(10):1472-1477. doi: 10.1038/s41565-024-01729-8. Epub 2024 Jul 17.
Optical monitoring of the position and alignment of objects with a precision of only a few nanometres is key in applications such as smart manufacturing and force sensing. Traditional optical nanometrology requires precise nanostructure fabrication, multibeam interference or complex postprocessing algorithms, sometimes hampering wider adoption of this technology. Here we show a simplified, yet robust, approach to achieve nanometric metrology down to 2 nm resolution that eliminates the need for any reference signal for interferometric measurements. We insert an erbium-doped quartz crystal absorber into a single Fabry-Pérot cavity with a length of 3 cm and then induce exceptional points by matching the optical loss with the intercavity coupling. We experimentally achieve a displacement response enhancement of 86 times compared with lossless methods, and theoretically argue that an enhancement of over 450 times, corresponding to subnanometre resolution, may be achievable. We also show a fivefold enhancement in the signal-to-noise ratio, thus demonstrating that non-Hermitian sensors can lead to improved performances over the Hermitian counterpart.
对物体的位置和对准进行精度仅为几纳米的光学监测在智能制造和力传感等应用中至关重要。传统的光学纳米计量学需要精确的纳米结构制造、多光束干涉或复杂的后处理算法，这有时会阻碍该技术的更广泛应用。在此，我们展示了一种简化但稳健的方法，可实现低至2纳米分辨率的纳米计量，该方法无需用于干涉测量的任何参考信号。我们将掺铒石英晶体吸收器插入一个长度为3厘米的单法布里-珀罗腔中，然后通过使光损耗与腔内耦合相匹配来诱导例外点。与无损方法相比，我们通过实验实现了86倍的位移响应增强，并且从理论上认为，可能实现超过450倍的增强，对应于亚纳米分辨率。我们还展示了信噪比提高了五倍，从而证明非厄米传感器可以比厄米传感器具有更好的性能。
