Electrically Tunable Singular Phase and Goos–Hänchen Shifts in Phase‐Change‐Material‐Based Thin‐Film Coatings as Optical Absorbers

Abstract

The change of the phase of light under the evolution of a nanomaterial with time is a promising new research direction. A phenomenon directly related to the sudden phase change of light is the Goos–Hänchen (G–H) shift, which describes the lateral beam displacement of the reflected light from the interface of two media when the angles of incidence are close to the total internal reflection angle or Brewster angle. Here, an innovative design of lithography‐free nanophotonic cavities to realize electrically tunable G–H shifts at the singular phase of light in the visible wavelengths is reported. Reversible electrical tuning of phase and G–H shifts is experimentally demonstrated using a microheater integrated optical cavity consisting of a dielectric film on an absorbing substrate through a Joule heating mechanism. In particular, an enhanced G–H shift of 110 times of the operating wavelength at the Brewster angle of the thin‐film cavity is reported. More importantly, electrically tunable G–H shifts are demonstrated by exploiting the significant tunable phase change that occurs at the Brewster angles, due to the small temperature‐induced refractive index changes of the dielectric film. Realizing efficient electrically tunable G–H shifts with miniaturized heaters will extend the research scope of the G–H shift phenomenon and its applications.

A voltage-controllable VO2 based metamaterial perfect absorber for CO2 gas sensing application

“…25 VO 2 is a well-known material while the insulator-to-metal transition characteristic can be induced thermally, optically or electrically at the time scale of picoseconds due to the atomic level deformation for sensing applications or active phase change material-based control. 26–32 By improving the internal temperature above the critical temperature, dramatic changes of electrical conductivity can be realized in VO 2 . They are reflected in the optical dielectric properties of VO 2 to control the propagation of EM waves with high efficiency.…”

Ultrawide‐Angle Ultralow‐Reflection Phenomenon for Transverse Electric Mode in Anisotropic Metasurface

“…[1] Based on the Fresnel formula, [2] for the case of transverse magnetic (TM)-polarized light incident at the Brewster angle, the reflection would disappear and a transparency response is obtained, which is named as the Brewster effect. During the past centuries, the Brewster effect has been widely utilized in many optical applications, such as polarizers, [3][4][5][6] dielectric properties quantifying, [7][8][9] Brewster angle microscopy, [10][11][12] extraordinary optical transmission, [13][14][15] and optical broadband angular selectivity. [16][17][18] These traditional applications are usually limited to TM, or p-polarized electromagnetic (EM) waves, the essence of which is the characteristic impedance matching between two media only being achievable at a fixed Brewster angle and under TM wave incidence.…”

Ultra‐Stable Phase Change Coatings by Self‐Cross‐Linkable Reactive Poly(ethylene glycol) and MWCNTs

“…It is quite convenient and suitable for large‐scale application, whereas only few works were reported with respect to PCMs coatings. [ 32 ] The reasons can be concluded as: 1) PCMs content could not reach a sufficient level for efficient thermal adjustment in the case of using them as nanofiller. [ 33,34 ] 2) Reactivity of PCMs component is not high enough, so photo or thermal initiating, high temperature curing, or post‐treatment is inevitable.…”