Engineering the phase front of light with phase-change material based planar lenses.
A novel hybrid planar lens is proposed to engineer the far-field focusing patterns. It consists of an array of slits which are filled with phase-change material Ge2Sb2Te5 (GST). By varying the crystallization level of GST from 0% to 90%, the Fabry-Pérot resonance supported inside each slit can be spectrally shifted across the working wavelength at 1.55 µm, which results in a transmitted electromagnetic phase modulation as large as 0.56π. Based on this geometrically fixed platform, different phase fronts can be constructed spatially on the lens plane by assigning the designed GST crystallization levels to the corresponding slits, achieving various far-field focusing patterns. The present work offers a promising route to realize tunable nanophotonic components, which can be used in optical circuits and imaging applications.
1] The Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom [2] Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore.
Yiguo
Y
Chen
State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Science, Chengdu, 610209, China.
Xiong
X
Li
Inst. NEEL, CNRS, 25 rue des Martyrs BP 166, 38042 Grenoble cedex 9, France.
Yannick
Y
Sonnefraud
Departamento de Fisica Teorica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autonoma de Madrid, E-28049 Madrid, Spain.
Antonio I
AI
Fernández-Domínguez
State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Science, Chengdu, 610209, China.
Xiangang
X
Luo
Department of Electrical and Computer Engineering, National University of Singapore, 117576, Singapore.
Minghui
M
Hong
The Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom.
Stefan A
SA
Maier