Dynamic Transmissive Metasurface for Broadband Phase‐Only Modulation Based on Phase‐Change Materials

Abstract

Dynamic metasurfaces provide exciting opportunities for spatial light modulation with ultra‐compact footprint and high resolution. Designs reported so far typically suffer from efficiency problem due to the strong coupling between amplitude and phase modulation. Huygens metasurface design eliminates the back propagation with interference of dual resonances, offering a potential solution for phase‐only modulation. However, the intrinsic dispersion mismatch between the dual modes restricts this design to a highly limited bandwidth. Here, a dynamic phase‐change metasurface design that enables transmissive phase modulation covering over 240° with high‐level transmisstance maintained over 0.8 and a large operation bandwidth of 80 nm ranging from 1516 to 1596 nm, is presented. To verify the potential usage of this design, a multi‐state phase‐change control scheme that enables quasi‐continuous phase modulation is further provided. The key feature of this design is the leverage of congener Huygens concept. Judicious incorporation of lossless phase‐change material (PCM) with congener Huygens metasurface allows wideband holding of Huygens condition, which provides a perfect platform to simultaneously address the efficiency and bandwidth problems. This novel feature represents a meaningful step forward to integrate spatial light modulation.

Fabrication and integration of photonic devices for phase-change memory and neuromorphic computing

“…As characterized by AFM, density of wrinkles was significantly reduced after implementing a hot-water bath expansion approach [229]. Above techniques of large-area graphene transfer are also crucial for fabricating electrically reconfigurable metasurface devices in phase, deflection, and focal length manipulation [84,85,231,232]. Fabrication of plasmonic nanogap devices rely on precise overlay alignment, as shown in figure 9.…”

Optimizing Wavelength for Enhanced Cycling Durability of Laser‐Induced Phase Change in Sb2S3 Films: A Survey on Optical Transmission Phase Shift

“…Notably, higher cycling durability was achieved using multiple pulses, where the rising pulse energy exceeded that in the single pulse test depicted in Figure 5c. Since the cooling time (<1 ms) from the melting point of SbS to the room temperature [36,50,51] is very short, the film has cooled down from the previous pulses before being irradiated by the subsequent ones for a pulse interval of 150 ms. Thus, it can be inferred that no temperature accumulation effect is involved in this outcome.…”

Reconfigurable Micro/Nano‐Optical Devices Based on Phase Transitions: From Materials, Mechanisms to Applications

“…To address this problem, alternative types of external heaters that are transparent to incident light are theoretically proposed to enable transmissive metasurface designs. [ 151 , 152 , 153 ] These schemes are inspiring and remain to be demonstrated through experiments.…”