摘要
The realization of active modulation of reflection phase based on metasurfaces is of great significance for flexible control of electromagnetic wavefront,which makes metasurfaces have practical application values in polarization conversion,beam steering,metalens,etc.In this paper,a reflection phase tunable gap-surface plasmon(GSP)metasurface based on phase change materials Ge_(2)Sb_(2)Te_(5)(GST)is designed and experimentally demonstrated.By virtue of the characteristics of large permittivities difference before and after GST phase transition and the existence of stable intermediate states,the continuous modulation of near-infrared reflection phase larger than 200°has been realized.At the same time,through the reasonable design of the structure sizes,the reflection has been maintained at about 0.4 and basically does not change with the GST phase transition,which improved the working efficiency of the metasurface significantly.In addition,the coupled-mode theory(CMT)is introduced to make a full analysis of the modulation mechanism of the reflection phase,which proves that the phase transition of GST can induce the transition of metasurface working state from overcoupling mode to critical coupling mode.The improvement of the metasurface working efficiency has practical values for wavefront modulation.
作者
Ce Li
Wei Zhu
Shuo Du
Junjie Li
Changzhi Gu
李策;朱维;杜硕;李俊杰;顾长志(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Physical Sciences,CAS Key Laboratory of Vacuum Physics,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Space Applied Physics and Chemistry,Ministry of Education and Department of Applied Physics,School of Science,Northwestern Polytechnical University,Xi'an 710129,China;Songshan Lake Materials Laboratory,Dongguan 523808,China;Collaborative Innovation Center of Quantum Matter,Beijing 100871,China)
基金
the National Key Research and Development Program of China(Grant Nos.2016YFA0200400,2016YFA0200800,and 2016YFA0300601)
the National Natural Science Foundation of China(Grant Nos.61888102,11674387,11974386,and 61905274)
the Strategic Priority Research Program and Key Research Program of Frontier Sciences of Chinese Academy of Sciences(Grant Nos.XDB33000000,XDB28000000,and QYZDJ-SSW-SLH042).
