Self-Organized 3D Photonic Superstructure: Blue Phase Liquid Crystal

Abstract

Blue phase liquid crystals (BPLCs) have attracted considerable attention in recent years owing to their unique periodic structure and electro-optic properties. Besides the potential applications in the next generation display, BPLC with a cubic lattice structure can be regarded as a self-organized three-dimenstional (3D) photonic crystal that can be applied for photonic devices such as optical filter, optical attenuator, phase modulator, laser source and so on. This chapter will introduce the formation of BPLCs from both theoretical and experimental points of view. The stability and temperature range of BPLCs are also discussed followed by its photonic crystal structure, lattice orientation and phase identification. After a basic overview, this chapter will further introduce the applications of BPLCs, including controllability of photonic band gap with external fields, fast electro-optic Kerr effect, and optical nonlinear effect. This short summary shows that the century old intriguing BPLCs have diverse opportunities to offer in modern photonic materials and devices. Moreover, the current challenges in this area are expected to spark innovative ideas leading toward the design and engineering of new chiral materials that may furnish suitable BPLCs to produce advanced photonic materials that have desirable properties and functions.

Fast self-assembly of macroscopic blue phase 3D photonic crystals

“…Blue phase (BP) liquid crystals are materials with unique self-assembling properties that make them promising candidates for novel photonic applications. BPs self-organize spontaneously in 3D structures with sub-micrometer range periodicity; as a result, they can be considered 3D photonic crystals [1,2].…”

“…The structure of BPs [2] is fairly complex, molecules arrange in helices that assemble in double-twisted cylinders which in turn organize in cubic crystals. It is important to realize that the unit-cell sizes range in the 100's nm range, thus qualifying these structures for generation of unique optical phenomena such as photonic gaps and spectral filters.…”

All-Optically Controllable Photonic Crystals Based on Chiral-Azobenzene-Doped Blue Phase Liquid Crystals

“…BPIII is amorphous, and BPI and BPII have cubic structures, corresponding to body-centered and simple cubic symmetries, respectively. The self-assembly 3D cubic structures of BPI and BPII are composed of orderly stacked double-twisted cylinders; thus, cubic BPLCs can be regarded as photonic crystals (PhCs) that possess a unique photonic bandgap (PBG) and show colorful reflection characteristics [16].…”

Symmetric Continuously Tunable Photonic Band Gaps in Blue-Phase Liquid Crystals Switched by an Alternating Current Field

“…As one of soft artificial 3D-PCs, blue-phase (BP) liquid crystals (BPLCs) have selective Bragg reflections of light in the visible wavelength due to their spontaneous, self-assembled, and 3D cubic structures. , So far, three types of BPs are reported, including BPIII of isotropic symmetry, BPII of the simple cubic structure, and BPI of the body-centered cubic structure. , Compared with the aforementioned techniques, the 3D-PCs fabricated with BPLCs have strengths of simple, fast, and low cost. More importantly, the BPLCs possess the greatest strengths in the soft PC area for their superior flexibility. − Recent progress by applying an electric field as the external stimuli opens an important door toward the wide tunable range of the photonic band gap (PBG) of 3D-PC BPLCs.…”

“…As one of soft artificial 3D-PCs, blue-phase (BP) liquid crystals (BPLCs) have selective Bragg reflections of light in the visible wavelength due to their spontaneous, self-assembled, and 3D cubic structures. 26,27 So far, three types of BPs are reported, including BPIII of isotropic symmetry, BPII of the simple cubic structure, and BPI of the body-centered cubic structure. 28,29 Compared with the aforementioned techniques, the 3D-PCs fabricated with BPLCs have strengths of simple, fast, and low cost.…”