Tunable metalensing based on plasmonic resonators embedded on thermosresponsive hydrogel

Abstract

Metalenses of adjustable power and ultrathin flat zoom lens system have emerged as a promising and key photonic device for integrated optics and advanced reconfigurable optical systems. Nevertheless, realizing an active metasurface retaining lensing functionality in the visible frequency regime has not been fully explored to design reconfigurable optical devices. Here, we present a focal tunable metalens and intensity tunable metalens in the visible frequency regime through the control of the hydrophilic and hydrophobic behavior of freestanding thermoresponsive hydrogel. The metasurface is comprised of plasmonic resonators embedded on the top of hydrogel which serves as dynamically reconfigurable metalens. It is shown that the focal length can be continuously tuned by adjusting the phase transition of hydrogel, the results reveal that the device is diffraction limited in different states of hydrogel. In addition, the versatility of hydrogel-based metasurfaces is further explored to design intensity tunable metalens, that can dynamically tailor the transmission intensity and confined it into the same focal spot under different states, i.e., swollen and collapsed. It is anticipated that the non-toxicity and biocompatibility make the hydrogel-based active metasurfaces suitable for active plasmonic devices with ubiquitous roles in biomedical imaging, sensing, and encryption systems.

Metalens in Improving Imaging Quality: Advancements, Challenges, and Prospects for Future Display

“…[174] The fabrication of tunable metalens utilizing phase change materials that are light-sensitive and heat-sensitive is the main component of photothermal tuning. [175][176][177][178][179][180] For polarization-sensitive metalens, the focal length of the metalens can be tuned by adjusting the orbital angular momentum of the incident light, or the tunability can be realized by altering the polarization state of incident light. [181][182][183] The phase change materials most utilized generally in the application of dynamic metalens made of materials sensitive to light or heat include chorionic phase change materials, [184,185] vanadium dioxide, [186,187] Ge 2 Sb 2 Se 4 Te (GSST), [188][189][190][191][192][193] graphene, [194] germanium antimony tellurium thin film, [195] water, [196] etc.…”