Near-Infrared Rewritable, Non-Volatile Subwavelength Absorber Based on Chalcogenide Phase Change Materials

Abstract

Chalcogenide phase change materials enable the realization of novel, non-volatile, switchable electronic and photonic devices. In this paper, we propose a type of rewritable, non-volatile near infrared subwavelength absorber based on chalcogenide phase change materials. Our numerical simulations show that nearly perfect absorption more than 0.99 can be realized in the written state while the absorption of as-deposited or erased state is lower than 0.15 in the studied spectral range, leading to high contrast ratio of reflection more than 20 dB. Continuous tuning of the absorption spectra can be realized not only by varying the geometric parameters of the absorber but also by changing the crystallization ratio of the switched Ge 2 Sb 2 Te 5 (GST). The proposed device may find widespread applications in optical modulation, beam steering and so on.

High Q Resonant Sb2S3-Lithium Niobate Metasurface for Active Nanophotonics

“…Then, we fix the duty cycle f = 0.5, and study the reflection spectra corresponding to different crystalline fractions of . Here, the relationship between the effective dielectric constant of the and the crystalline fraction is given by the Lorenz-Lorentz relationship [ 31 ]: where and are the wavelength-dependent permittivity of crystalline and amorphous , respectively. And is the effective dielectric constant of the hybridization .…”

“…Then, we fix the duty cycle f = 0.5, and study the reflection spectra corresponding to different crystalline fractions η of Sb 2 S 3 . Here, the relationship between the effective dielectric constant of the Sb 2 S 3 and the crystalline fraction η is given by the Lorenz-Lorentz relationship [31]:…”

“… (GST) and are probably the commonest PCMs in nanophotonics [ 4 , 5 , 6 ]. They are widely used in applications such as dynamic thermal emission [ 7 , 8 , 9 , 10 ], light modulation [ 11 , 12 , 13 , 14 , 15 , 16 , 17 ], beam steering [ 18 , 19 ], polarization conversion [ 20 ], colour display [ 21 , 22 , 23 ] and various tunable metasurfaces and metadevices [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. Customized laser has already been used to write, erase, and rewrite GST films into two-dimensional binary or gray-scale functional patterns, which would induce local refractive index changes and construct nanophotonic devices [ 36 ].…”

High Q Resonant Graphene Absorber with Lossless Phase Change Material Sb2S3

“…Phase change materials (PCM), such as Ge 2 Sb 2 Te 2 (GST) and VO 2 , have has been used in optically tunable nanophotonic devices for a long time [30][31][32], such as thermal camouflage [33], dynamic color display [34][35][36], beam steering [37], and light modulation [38][39][40][41]. Previous work has been able to write, erase, and rewrite two-dimensional binary or gray-scale functional patterns into nano-scale GST films through customized lasers, to induce local refractive index changes and construct nanophotonic devices [42,43]. Electrode heating can also be applied to write and erase the patterns in GST, achieving a polarization-insensitive phase gradient metasurface [44].…”

Reconfigurable Flat Optics with Programmable Reflection Amplitude Using Lithography‐Free Phase‐Change Material Ultra‐Thin Films

“…By introducing PCMs in similar engineered thin-films, recent works demonstrated tunable structural coloration, [15,16] optically reconfigurable metasurfaces, [17] or tunable near-perfect absorption. [18][19][20][21][22][23][24]25] So far, these experimental works demonstrated actively switchable optics that are either binary and/or volatile. However, the complex features of chalcogenide PCMs, and most notably the possibility to actively set them into a state of controlled partial crystallization, may be used to a much deeper extent.…”