Laser emission in a 3D nanoporous polymer replica of amorphous blue phase III

Abstract

Wide-temperature polymer stabilized cubic blue phases (BPI and BPII) facilitated the emergence of practically feasible band-edge BP lasers. However, the mysterious "blue fog" amorphous BPIII always remained elusive in terms of its applicability to photonic devices due to its random amorphous structure devoid of photonic bandgaps and due to the difficulty in effectively identifying and stabilizing it for practical applications. We present the first photonic device based on amorphous BPIII by demonstrating that a three-dimensional BPIII polymer scaffold or template, when infiltrated with liquid crystal and laser dye, forms a system where random lasing action is generated due to multiple scattering events occurring in the nanoporous and disordered polymer replica of BPIII. This study represents a facile approach for the development of photonic devices which favorably exploit unique polymer network morphologies for laser emission.

Nonlinear Rheology and Fracture of Disclination Network in Cholesteric Blue Phase III

“…However, absence of the platelet texture and dark blue texture do not always indicate the formation of BPIII, as Kim and Chien presented [22]. Chien et al provided an accurate method to distinguish BPIII from other BPs by observing optical activity [21,24,25]. Figure 2 shows polarized microscope image at T = 35.1 • C. Image in the center was taken under crossed polarizers, while images on left and right sides were taken at deviation angle between the analyzer and polarizer of φ = ±4 • by following the method established by Chien's group [21,24].…”

A random laser based on electrospun polymeric composite nanofibers with dual-size distribution

“…The development of novel polymer nanober-based photonic devices has attracted a great deal of attention due to the improved functional, optical and mechanical properties of organic materials. 1,2 Random lasers (RLs) are specic lasers in which conventional feedback mechanisms based on a Fabry-Perot cavity are substituted by scattering in disordered media. As reported in ref.…”

Advancements and Applications of Liquid Crystal/Polymer Composite Films

“…L iquid crystals (LCs) are materials with the fluid-like mobility of liquids and the long-range ordering characteristics of crystalline solids that exhibit orientational order in the arrangement of molecules. 1 The thermotropic LCs which have extensively been applied in liquid-crystal displays (LCDs) can have nematic phase, 2 smectic phase, 3 cholesteric phase, 4 blue phases (BPs), 5 discotic phase (Figure 1), 6 twist bend (TB) phase (Figure S1), 7 and twist grain boundary (TGB) phase 8 (Figure S2). The nematic phase is one of the most common types of LC phases, wherein the molecules exhibit orientational order only along the long molecular axis (called the director) (Figure 1a).…”

“…1−4 BPs are mesophases appearing over a narrow temperature range between the cholesteric and isotropic phases, and they are divided into BPI (Figure 1e), BPII (Figure 1f), and BPIII (Figure 1g). 5 Shape-anisotropic molecules with non-rod-like properties are also disk or bent-core molecules; disk molecules can orient themselves in a layer-like structure to form a discotic phase, called a discotic columnar phase, and can exhibit order or disorder within the columns (referring to the stacking of disks) (Figure 1h). 6 The TB phase possesses a heliconical structure with a pitch ranging from several to tens of nanometers, which originates from the twist and bend deformations of bent molecules (Figure S1).…”

“…The nematic phase is one of the most common types of LC phases, wherein the molecules exhibit orientational order only along the long molecular axis (called the director) (Figure a). The smectic phase presents a layered structure, wherein the director points along the layer normal (Figure b) and tilts (Figure c), whereas the cholesteric phase exhibits a spontaneous helical structure with a twist axis perpendicular to the local director due to the constituent chiral molecules (Figure d). − BPs are mesophases appearing over a narrow temperature range between the cholesteric and isotropic phases, and they are divided into BPI (Figure e), BPII (Figure f), and BPIII (Figure g) . Shape-anisotropic molecules with non-rod-like properties are also disk or bent-core molecules; disk molecules can orient themselves in a layer-like structure to form a discotic phase, called a discotic columnar phase, and can exhibit order or disorder within the columns (referring to the stacking of disks) (Figure h) .…”