Coupling of Defect Modes in Cholesteric Liquid Crystals Separated by Isotropic Polymeric Layers

Gao, Shaohua; Zhai, Yujia; Zhang, Xinzheng; Song, Xiang; Wang, Jiayi; Drevenšek‐Olenik, Irena; Rupp, R. A.; Xu, Jingjun

doi:10.3390/polym10070805

Cited by 13 publications

(13 citation statements)

References 37 publications

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“…Figure 2d reveals a dominant right circular polarization (RCP) component with a small amount of left circular polarization light. For an isotropic defect layer, which is the configuration used here, previous research has shown that the polarization of the mode is typically observed to be circularly polarized of the same handedness as that of the CLC helix 34–36. Our results are in broad agreement in that we see a dominant RCP component in accordance with the right‐handed helix of our CLC layers.…”

Section: Figuresupporting

confidence: 86%

A Thin‐Film Flexible Defect‐Mode Laser

Ali

Lin

Snow

et al. 2020

Advanced Optical Materials

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Laser emission from a flexible defect‐mode structure consisting of two photopolymerized liquid crystal thin films separated by a dye‐doped polymethylmethacrylate defect layer is demonstrated. A simple and cost‐effective film transfer technique is used to fabricate the flexible laser and the corresponding laser emission characteristics, which shows single‐mode laser emission at λ = 582 nm, with an excitation threshold of Eth = 12.3 ± 0.5 µJ cm−2 per pulse and a slope efficiency of ηs = 6.0 ± 0.3%, are presented. The polarization state of the laser emission are also presented and are compared with the findings reported in the literature. Finally, laser‐beam steering is demonstrated up to 42° by subjecting the device to a mechanically induced deformation that creates a radius of curvature of 5 mm, which is of potential interest for conformable and wearable technology platforms.

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Section: Figuresupporting

confidence: 86%

A Thin‐Film Flexible Defect‐Mode Laser

Ali

Lin

Snow

et al. 2020

Advanced Optical Materials

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“…Here we employ such unique properties of CLCs to realize tunable topological lasers at low cost. We analyze the coupling of defect modes in the P-CLC superlattices and demonstrate that the mini-bands can be designed in the bandgap of the CLC, which has been proposed to achieve visible defect mode lasing with a low threshold [57]. In experiments, we apply an out-of-plane liquid crystal orientation technology based on the femtosecond laser direct writing (FLDW) method recently developed by our group [58].…”

Section: Resultsmentioning

confidence: 99%

“…As shown in Fig 1(a, b1), the distances between the weakly and strongly coupled ribbons are chosen to be d 1 = 34×(p/2) and d 2 = 22×(p/2), respectively. The width of each polymer ribbon is set to be d i = 2 μm, which is thick enough to give rise to two defect modes in the bandgap of the CLC [57]. The two P-CLC SSH superlattices in either side of the interface have the same mini-band structure, but they possess different topological properties that are characterized by their winding numbers [60][61][62][63].…”

Section: Resultsmentioning

confidence: 99%

Topological Interface-state Lasing in a Polymer-Cholesteric Liquid Crystal Superlattice

Zhang

Wang

Yang

et al. 2022

Preprint

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The advance of topological photonics has heralded a revolution for manipulating light as well as for the development of novel photonic devices such as topological insulator lasers. Here, we demonstrate topological lasing of circular polarization in a polymer-cholesteric liquid crystal (P-CLC) superlattice, tunable in the visible wavelength regime. By use of the femtosecond-laser direct-writing and self-assembling techniques, we establish the P-CLC superlattice with a controlled mini-band structure and a topological interface defect, thereby achieving a low threshold for robust topological lasing at about 0.4 mJ. Thanks to the chiral liquid crystal, not only the emission wavelength is thermally tuned, but the circularly polarized lasing is readily achieved. Our results bring about the possibility to realize compact and integrated topological photonic devices at low cost, as well as to engineer an ideal platform for exploring topological physics that involves light-matter interaction in soft-matter environments.

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“…Furthermore, these materials self-organize their periodic structure and form a photonic bandgap (PBG) where circularly polarized light with the same handedness as that of the CLC helix cannot propagate [ 6 ]. Several studies on chiral photonic crystals have shown that it is possible to create localized optical modes within the PBG by inducing a defect into the periodic structure [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Multimode Robust Lasing in a Dye-Doped Polymer Layer Embedded in a Wedge-Shaped Cholesteric

et al. 2021

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Cholesteric liquid crystals (CLCs) with induced defects are one of the most prominent materials to realize compact, low-threshold and tunable coherent light sources. In this context, the investigation of optical properties of induced defect modes in such CLCs is of great interest. In particular, many studies have been devoted to the spectral control of the defect modes depending on their thickness, optical properties, distribution along the CLC, etc. In this paper, we investigate the lasing possibilities of a dye-doped polymer layer embedded in a wedge-shaped CLC. We show that multimode laser generation is possible due to the observed multiple defect modes in the PBG that enlarges the application range of the system. Furthermore, our simulations based on a Berreman 4 × 4 matrix approach for a wide range of CLC thickness show both periodic and continuous generation of defect modes along particular spectral lines inside the PBG. Such a robust spectral behaviour of induced defect modes is unique, and, to our knowledge, is not observed in similar CLC-based structures.

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Coupling of Defect Modes in Cholesteric Liquid Crystals Separated by Isotropic Polymeric Layers

Cited by 13 publications

References 37 publications

A Thin‐Film Flexible Defect‐Mode Laser

A Thin‐Film Flexible Defect‐Mode Laser

Topological Interface-state Lasing in a Polymer-Cholesteric Liquid Crystal Superlattice

Multimode Robust Lasing in a Dye-Doped Polymer Layer Embedded in a Wedge-Shaped Cholesteric

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