By virtue of great sensitivity to external stimuli, Blue-phase photonic crystal (BPPC) paves the efficient way for acquiring a tunable photonic crystal to fulfill dynamic photonic devices and enable active light control in three dimensions. To make BPPC feasible for practical photonic applications, we direct our research effort to few aspects including the fabrication of large-domain mono-crystalline lattice, the manipulation and characterization of lattices structures, and the demonstration of BPPC-based/incorporated applications.

Fabrication of large monocrystalline BPPC

　　For fabricating large three-dimensional photonic crystal, the technologies are still fraught with material processing and cost issues. Here, we develop a gradient-temperature technique that makes giant single photonic crystal based on blue phases realized. The three-dimensional photonic crystal with lateral dimensions of ~1cm and thickness of ~100μm is demonstrated.

Nature Communications  8, Article number: 727 (2017)

Lattice structure manipulation

　　Blue phase liquid crystals (BPLCs) shape a bright future in the development of photonics and various electro-optic applications by virtue of their unique characteristics like self-assemble 3D lattice structures. In spite of the remarkable features, BPLCs are subject to the limitation that the thermodynamically stable structures are only body-centered cubic and simple cubic for BPI and BPII, respectively. The non-cubic BPLCs are demonstrated only in the presence of an electric field, and they tend to restore to the original cubic structure upon the removal of an external field. Herein, we propose a method, repetitively applied field (RAF) technique, to get rid of the constraint and make non-cubic BPLCs stable without an electric field. By RAF technique, the spectrum of thermodynamically stable lattice structure of BPLC is extended, covering orthorhombic and tetragonal lattice structure. The results present many possibilities for advanced photonic, electro-optic and nonlinear applications.

Nature Materials   (2019)

Photonic band gap engineering of BPPC

　　Highly tunable 3D liquid photonic crystals are demonstrated using low-dc-field-driven polymer-stabilized blue phase liquid crystals. The central wavelength of the photonic band gap can be reversibly shifted to more than 200 nm away from the original position by using low DC-field. It shows the great potential in bandgap engineering by using such soft photonic crystal. We envision polymer-stabilized blue-phase liquid crystals as a fascinating platform for photonic applications, such as 3D lasers, nonlinear optics, and photonic integrated circuits.

ACS Photonics   2, Article number: 1524 (2015)