PubCard - Polarization-switchable plasmonic emitters based on laser-induced bubbles

(Peer-Reviewed) Polarization-switchable plasmonic emitters based on laser-induced bubbles

Jianjun Chen ¹ ² ³ ⁴ ⁵ 陈建军, Fengyuan Gan 甘峰源 ²

¹ Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
中国北京北京师范大学物理学系北京市应用光学重点实验室
² State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
中国北京北京大学人工微结构和介观物理国家重点实验室
³ Peking University Yangtze Delta Institute of Optoelectronics, Nantong 226010, China
中国北京北京大学长三角光电科学研究院
⁴ Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
中国北京北京大学纳光电子前沿科学中心量子物质科学协同创新中心
⁵ Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
中国太原山西省极端光学协同创新中心

Opto-Electronic Advances, 2022-05-27

https://doi.org/10.29026/oea.2022.200100

https://www.oejournal.org/article/doi/10.29026/oea.2022.200100

Abstract

Owing to weak light-matter interactions in natural materials, it is difficult to dynamically tune and switch emission polarization states of plasmonic emitters (or antennas) at nanometer scales. Here, by using a control laser beam to induce a bubble (n=1.0) in water (n=1.333) to obtain a large index variation as high as |Δn|=0.333, the emission polarization of an ultra-small plasmonic emitter (~0.4λ2) is experimentally switched at nanometer scales.

The plasmonic emitter consists of two orthogonal subwavelength metallic nanogroove antennas on a metal surface, and the separation of the two antennas is only sx=120 nm. The emission polarization state of the plasmonic emitter is related to the phase difference between the emission light from the two antennas. Because of a large refractive index variation (|Δn|=0.333), the phase difference is greatly changed when a microbubble emerges in water under a low-intensity control laser.

As a result, the emission polarization of the ultra-small plasmonic emitter is dynamically switched from an elliptical polarization state to a linear polarization state, and the change of the degree of linear polarization is as high as Δγ≈0.66.