近日，韩国蔚山国立科学技术研究院的Jongwon Lee及其研究团队取得一项新进展。经过不懈努力，他们成功利用子带间极化超表面产生电可调谐三次谐波。相关研究成果已于2024年7月17日在国际知名学术期刊《光：科学与应用》上发表。

在这项研究中，研究人员首次报道了使用基于MQW的子带间极化超表面实现中红外三次谐波产生(THG)的电调制特性，该超表面具有电可调谐的三阶非线性响应。实验中，研究人员实现了450%的THG信号调制深度，86%的零阶THG衍射调谐抑制基于超过180度的局部相位调谐，以及使用相位梯度的THG光束控制。这项研究工作提出了一种具有多种功能的电可调谐平面非线性光学元件的新途径。

据悉，非线性子带间极化子超表面将多个量子阱(MQWs)的子带间跃迁和等离激元纳米谐振器产生的巨大非线性响应集成在一起，不仅促进了几十kW cm^-2量级的泵浦强度下的有效频率转换，而且还实现了单个超原子水平上非线性响应的电调制和动态光束操纵。非线性光响应的幅度和相位的电调制特性是通过子带间非线性共振的斯塔克调谐实现的。

附：英文原文

Title: Electrically tunable third-harmonic generation using intersubband polaritonic metasurfaces

Author: Park, Seongjin, Yu, Jaeyeon, Boehm, Gerhard, Belkin, Mikhail A., Lee, Jongwon

Issue&Volume: 2024-07-17

Abstract: Nonlinear intersubband polaritonic metasurfaces, which integrate giant nonlinear responses derived from intersubband transitions of multiple quantum wells (MQWs) with plasmonic nanoresonators, not only facilitate efficient frequency conversion at pump intensities on the order of few tens of kW cm^-2 but also enable electrical modulation of nonlinear responses at the individual meta-atom level and dynamic beam manipulation. The electrical modulation characteristics of the magnitude and phase of the nonlinear optical response are realized through Stark tuning of the resonant intersubband nonlinearity. In this study, we report, for the first time, experimental implementations of electrical modulation characteristics of mid-infrared third-harmonic generation (THG) using an intersubband polaritonic metasurface based on MQW with electrically tunable third-order nonlinear response. Experimentally, we achieved a 450% modulation depth of the THG signal, 86% suppression of zero-order THG diffraction tuning based on local phase tuning exceeding 180 degrees, and THG beam steering using phase gradients. Our work proposes a new route for electrically tunable flat nonlinear optical elements with versatile functionalities.

DOI: 10.1038/s41377-024-01517-y

Source: https://www.nature.com/articles/s41377-024-01517-y