Tunable nanophotonics enabled by chalcogenide phase-change materials

Abstract

<jats:title>Abstract</jats:title><jats:p>Nanophotonics has garnered intensive attention due to its unique capabilities in molding the flow of light in the subwavelength regime. Metasurfaces (MSs) and photonic integrated circuits (PICs) enable the realization of mass-producible, cost-effective, and efficient flat optical components for imaging, sensing, and communications. In order to enable nanophotonics with multipurpose functionalities, chalcogenide phase-change materials (PCMs) have been introduced as a promising platform for tunable and reconfigurable nanophotonic frameworks. Integration of non-volatile chalcogenide PCMs with unique properties such as drastic optical contrasts, fast switching speeds, and long-term stability grants substantial reconfiguration to the more conventional static nanophotonic platforms. In this review, we discuss state-of-the-art developments as well as emerging trends in tunable MSs and PICs using chalcogenide PCMs. We outline the unique material properties, structural transformation, and thermo-optic effects of well-established classes of chalcogenide PCMs. The emerging deep learning-based approaches for the optimization of reconfigurable MSs and the analysis of light-matter interactions are also discussed. The review is concluded by discussing existing challenges in the realization of adjustable nanophotonics and a perspective on the possible developments in this promising area.</jats:p>

Dynamic Metasurfaces Using Phase‐Change Chalcogenides

“…The previously discussed reconfigurable properties of phase‐change metasurfaces are mainly relying on tailoring the amplitude response of incident light, thereby restricting their potential functionalities. Recently, an emerging research topic in the field of nanophotonics is to combine phase‐gradient metasurfaces with phase‐change medium, thereby extending the capability of dynamic wavefront shaping, such as reconfigurable beam‐steering, tunable metalens, and switchable photonic spin–orbit interactions . In the present section, we will review some of the research progress on dynamic phase‐change metasurfaces for active phase manipulation.…”

“…By applying electric current pulses, the phase states of GST meta‐atoms can be changed, resulting in selective modification. Very recently, the concept of selectively modulating each meta‐atom of the phase‐change metasurfaces has been proposed to a gate‐tunable GSP metasurface where the GST alloy functions as the feed gap between metallic structures . By utilizing the multistate phase transition of GST alloy from amorphous to the crystalline state, the GSP mode could be drastically modified.…”

Design for quality: reconfigurable flat optics based on active metasurfaces

“…Active metasurfaces have received concentrated attention recently, emerging as a promising area on the path toward practical implementations. While several review articles have covered the development of this field [19][20][21][22][23][24][25][26], we choose to approach this topic from a distinctive perspective by focusing on the design principles of active metasurfaces at optical frequencies (i.e., ultraviolet [UV] to infrared [IR]). We outline practical challenges and address how the design strategies are correlated to and can be harnessed to improve the performance of such metaoptical devices.…”

Reconfigurable all-dielectric metalens with diffraction-limited performance

“…Over the past few years, active metasurfaces have been investigated intensively [8][9][10][11][12][13][14][15][16] . Mechanical deformation or displacement of metasurfaces is an effective method for tuning metasurface devices or adaptively correcting optical aberrations [17][18][19][20][21][22] .…”

“…Phase change and phase transition materials (exemplified by chalcogenide compounds and correlated oxides such as VO2, respectively) offer another promising route for realizing active metasurfaces 15,[27][28][29] . The extremely large refractive index contrast associated with material phase transformation (e.g.…”