Large three-dimensional photonic crystals based on monocrystalline liquid crystal blue phases

Abstract

Although there have been intense efforts to fabricate large three-dimensional photonic crystals in order to realize their full potential, the technologies developed so far are still beset with various material processing and cost issues. Conventional top-down fabrications are costly and time-consuming, whereas natural self-assembly and bottom-up fabrications often result in high defect density and limited dimensions. Here we report the fabrication of extraordinarily large monocrystalline photonic crystals by controlling the self-assembly processes which occur in unique phases of liquid crystals that exhibit three-dimensional photonic-crystalline properties called liquid-crystal blue phases. In particular, we have developed a gradient-temperature technique that enables three-dimensional photonic crystals to grow to lateral dimensions of ~1 cm (~30,000 of unit cells) and thickness of ~100 μm (~ 300 unit cells). These giant single crystals exhibit extraordinarily sharp photonic bandgaps with high reflectivity, long-range periodicity in all dimensions and well-defined lattice orientation.

P‐146: Electrically Tunable Bandpass Filter with Narrow Bandwidth of 27 nm

“…The phase appears as black at higher field due to reflection peak shifted to UV region. We remarkable achieved the total reflection wavelength tuning in the spectral range of 240 nm, by applying the field ~29 V, which is wider than that of reported elsewhere [6][7][8]. On the other hand, the S2 and S3 shows the blue shift and green shift at spectral range of 95 nm and 80 nm, respectively.…”

“…More specifically, the P-146 / R. Manda band gap hysteresis is smaller than 10 nm for samples S2 and S3 while it is <20 nm for S1. The achieved hysteresis is relatively smaller by comparing it with similar literature where it is either huge or required special treatment [6,9,10]. It implies that the lattice distortion induced by the electric field was mostly recovered like field-induced refractive index.…”

“…The BPLC are also well-known for their great advantageous of easy processing, fast response, and optically isotropic phase [3,4,5]. Although the BPLC is having a great advantage of band gap tuning which can be utilized for color filter applications, the shorter operating range and unwanted multiple reflections due to intrinsic platelets deteriorates the device performance [6,7].…”

Multi-Wavelength Filters of Templated Blue Phase Liquid Crystal

“…In order to obtain a narrow bandwidth of blue phase liquid crystal devices, a single crystal blue phase liquid crystal or mono-domain blue phase liquid crystal can be used. Due to the complex preparation process and poor stability of a single crystal [25], the surface orientation method [26] was used to induce mono-domain BPLCs. Figure 3 shows the polarizing microscope images of PS-BPLC of the blue, green, and red color.…”

Orientation control of ideal blue phase photonic crystals

“…However, producing ideal BP crystals in large volumes remains a challenge. BPs have been previously produced as monocrystals by various methods, for instance, by orienting layers 4 , by long lasting applied voltage 5 , microwell confinement 6 , temperature gradient 7 or photopatterning 8 .…”