Nonvolatile Reconfigurable Phase‐Change Metadevices for Beam Steering in the Near Infrared

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. The development of flat, compact beam-steering devices with no bulky moving parts is opening up a new route to a variety of exciting applications, such as LIDAR scanning systems for autonomous vehicles, robotics and sensing, freespace, and even surface wave optical signal coupling. In this paper, the design, fabrication and characterization of innovative, nonvolatile, and reconfigurable beam-steering metadevices enabled by a combination of optical metasurfaces and chalcogenide phase-change materials is reported. The metadevices reflect an incident optical beam in a mirror-like fashion when the phase-change layer is in the crystalline state, but reflect anomalously at predesigned angles when the phase-change layer is switched into its amorphous state. Experimental angleresolved spectrometry measurements verify that fabricated devices perform as designed, with high efficiencies, up to 40%, when operating at 1550 nm. Laserinduced crystallization and reamorphization experiments confirm reversible switching of the device. It is believed that reconfigurable phase-change-based beam-steering and beam-shaping metadevices, such as those reported here, can offer real applications advantages, such as high efficiency, compactness, fast switching times and, due to the nonvolatile nature of chalcogenide phasechange materials, low power consumption.

Terahertz Beam Steering Technologies: From Phased Arrays to Field‐Programmable Metasurfaces

“…The optical properties of GST changes remarkably when a phase transition occurs from amorphous phase (α‐GST) to crystalline phase ( c ‐GST). For instance, the refractive index at 1550 nm is 3.8 and 5.5 for the α‐GST and c ‐GST, respectively . Tsai and co‐workers designed an active dielectric metasurface based on GST alloy in the near infrared (NIR) wavelengths .…”

Advanced Optical Programming of Individual Meta‐Atoms Beyond the Effective Medium Approach

“…This makes them ideally suited for photonic applications ranging from integrated optical memories over color displays to active MSs . For example, they have already been designed and successfully employed for applications such as polarization filtering, lensing, and beam steering …”

High-Efficiency, Broadband, Near Diffraction-Limited, Dielectric Metalens in Ultraviolet Spectrum

“…Metasurfaces have stirred up a spree of research interest in recent years due to their brilliant performance in the field of electromagnetic wave manipulation [1][2][3][4][5][6][7][8][9]. Metasurfaces are based on some well-designed subwavelength scale arrays of resonators to manipulate the amplitude, phase, propagation direction, and polarization of light to nanoscale resolution at an ease [10][11][12][13][14][15][16][17][18][19], making them an appropriate option for miniaturization and integration of photonic systems. Currently, metasurfaces are being applied to various applications, such as metalenses [20], holograms [21,22], cloaking [23,24], surface plasmon launcher [4], nonlinear devices [3,11,[25][26][27][28], bio sensing [26,27], computing [11,28], switching [5,29], and various novel photonic systems and devices [30][31][32][33][34].…”