Mid-infrared active metasurface based on Si/VO<sub>2</sub> hybrid meta-atoms
Tongtong Kang, Boyu Fan, Jun Qin, Weihao Yang, Shuang Xia, Zheng Peng, Бо Лю, Sui Peng, Xiao Liang, Tingting Tang, Longjiang Deng, Yi Luo, Hanbin Wang, Qiang Zhou, Lei Bi
Abstract
Active metasurfaces whose optical properties can be tuned by an external stimulus have attracted great research interest recently. Introduction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mml:mrow> </mml:math> phase change material in all-dielectric metasurfaces has been demonstrated to modulate the resonance wavelength and amplitude in the visible to near-infrared wavelength range. In this study, we report a mid-infrared active metasurface based on <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>Si</mml:mi> <mml:mo>/</mml:mo> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> hybrid meta-atoms. By incorporating <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> thin films in different locations of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>Si</mml:mi> <mml:mo>/</mml:mo> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> all-dielectric nanodisks, we demonstrate different modulation amplitude of the electric or magnetic resonance scattering cross sections, leading to drastically different transmission spectrum upon <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> insulator to metal phase transition. The physical mechanism is originated from the field profiles of the resonance modes, which interact with <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> differently depending on its locations. Based on this mechanism, we experimentally demonstrated a large modulation of the transmittance from 82% to 28% at the 4.6 μm wavelength. Our work demonstrates a promising potential of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mrow> <mml:mi>VO</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> -based active all-dielectric metasurface for mid-infrared photonic applications such as infrared camouflage, chemical/biomedical sensing, optical neuromorphic computing, and multispectral imaging.