Zhongyang Li's Group Makes New Progress in Active Manipulation of Dynamic Displays in Micro and Nano Optics

Recently, Advanced Functional Materials, an international authoritative journal, (IF=18.8) has online published two recent research works along the direction of dynamic display of micro/nano optics of Professor Zhongyang Li's group (Nanophotonics & Emerging Application Laboratory, NEAL) at the Electronic Information School.  The research work is carried out around the key direction of nanophotonics research "active control performance". 

Research 1: Real-Time Tunable Nanoprinting-Multiplexing with Simultaneous Meta-Holography Displays by Stepwise Nanocavities.

Although metasurface-based devices exhibit great potential in optical display and storage technology, the challenges in practical nanoantenna fabrication limit their wide application. In parallel, flat optics, including planar thin-film nanocavities, have also been extensively studied to realize various spectral engineering and imaging functionalities with large areas and simpler architecture. However, a longstanding practical challenge is to achieve multiplexing imaging functionalities with dynamic switchable ability in real-time, which to date remains unexplored. In this study, by utilizing the typical inflation sensitivity of hydrogels to humidity change, a multiplexing imaging tunable strategy based on stepwise metal–hydrogel–metal (MHM) nanocavities is originally explored and demonstrated to exhibit dynamic switchable red/green/blue multichannel nanoprinting in real-time. By decoupling the amplitude/phase correlation, MHM nanocavities successfully enable the hybrid encryption of simultaneous meta-holography with independent-encoding freedom in addition to multiplexing nanoprinting. Such an imaging approach, which employs a dynamic tuning scheme, paves a promising avenue toward various applications including state-of-the-art tunable imaging display/storage/encryption, humidity optical sensors, and next-generation dynamic augmented reality technology.

 
Figure 1. (a) Schematic illustrations for the MHM nanocavities. (b) Working principle and experimental observation of the dynamic imaging switch in real-time.

Research 2: Electric-Driven Meta-Optic Dynamics for Simultaneous Near-/Far-field Multiplexing Display.

Heading towards to intelligent photonic technology, meta-optics is in the revolutionary process of changing from passive to active controllable devices. Despite various emerging tuning mechanisms exploration and demonstration, they mainly focus on spectral amplitude alternation or near-field imaging switch. Most tuning schemes inevitably demand quite complicated nanofabrication to incorporate nanotextured active materials, thus limiting its applicable scenarios outside the laboratory. Hence, a practically accessible solution in real life to simultaneously realize multi-field (both near- and far-field) dynamic displays remains a critical challenge. Here, a practical electric-driven liquid-crystal-integrated metasurface (ELIM) is proposed and demonstrated toward advanced intelligent dynamic display. Through elaborately screening building block (α-Si nanopillar) geometry to build up a systematic architectural dictionary, conventional spatial-multiplexing is successfully achieved and the degeneracy for amplitude/phase selections is created and thus any arbitrary multi-field encryptions are allowed. By leveraging ELIM anisotropic characteristics for orthogonal polarizations, an electric-driven dynamic tuning is practically realized for the first time to enable quad-fold dynamic exhibitions, including switchable dual-nanoprinting (near-field) and simultaneous dual-holography (far-field) images with independent-encryption freedom. Overall, it is envisioned that meta-optics integrated with the liquid-crystal platform can easily find practical applications in real life for intelligent dynamic display, imaging multiplexing, information encryption/security, etc.

 
Figure 2. (a, b) Schematic illustrations for the ELIM (a) and liquid-crystal (b). (c, d) Photograph of the optical measurement setup. (e) Simulated and experimental results of nanoprinting and meta-holography for light incidence at the voltage of = 0 and = 5 V.

NEAL's research group has recently achieved a series of research achievements in the field of metasurface optical devices, and has published several works in Advanced Functional Materials (IF=18.8), Small (IF=13.3), Advanced Optical Materials (IF=9.9), ACS Applied Materials & Interfaces (IF=9.2) and other well-known journals in nanotechnology and optical devices.  NEAL's team will continue to advance innovation and research in the field of large-area active regulation and AR display in micro/nano optical devices.

Paper link:
1. Real‐Time Tunable Nanoprinting‐Multiplexing with Simultaneous Meta‐Holography Displays by Stepwise Nanocavities
2. Electric‐Driven Meta‐Optic Dynamics for Simultaneous Near‐/Far‐Field Multiplexing Display