Diffraction of cholesteric liquid crystal gratings probed by monochromatic light from 450 to 750 nm

Hung, Wen-Chi; Cheng, Wood-Hi; Liu, Tung-Kia; Jiang, I-Min; Tsai, Ming-Shiun; Yeh, Pochi

doi:10.1063/1.2990055

Cited by 8 publications

(5 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are three different modes. In the homogeneous cell [ 1 , 2 , 3 , 4 , 5 , 6 ], which is composed of two substrates with parallel alignment, the LC molecules spontaneously organize into planar helical layers with the helical axis perpendicular to the substrates. As illustrated in Figure 1 a, the helical pitch P is defined as the length of one turn of the helical structure.…”

Section: Introductionmentioning

confidence: 99%

Light-Driven Rotation and Pitch Tuning of Self-Organized Cholesteric Gratings Formed in a Semi-Free Film

Duan

Tang

et al. 2017

Polymers

View full text Add to dashboard Cite

Cholesteric liquid crystal (CLC) has attracted intensive attention due to its ability to form a periodic helical structure with broad tunability. CLC gratings in open systems are especially promising in sensing and micromanipulation. However, there is still much to learn about the inherent mechanism of such gratings. We investigate the light-driven rotation and pitch-tuning behaviors of CLC gratings in semi-free films which are formed by spin-coating the CLC mixtures onto planarly photoaligned substrates. The doped azobenzene chiral molecular switch supplies great flexibility to realize the continuous grating rotation. The maximum continuous rotational angle reaches 987.8 • . Moreover, dependencies of light-driven rotation and pitch tuning on the dopant concentration and exposure are studied. The model of director configuration in the semi-free film is constructed. Precise beam steering and synchronous micromanipulation are also demonstrated. Our work may provide new opportunities for the CLC grating in applications of beam steering, micromanipulation, and sensing.

show abstract

Section: Introductionmentioning

confidence: 99%

Light-Driven Rotation and Pitch Tuning of Self-Organized Cholesteric Gratings Formed in a Semi-Free Film

Duan

Tang

et al. 2017

Polymers

View full text Add to dashboard Cite

show abstract

“…In addition, the polarization sensitivity of the CLC grating is also investigated. As shown in Figure 3d, it is obvious that the spots diffracted from stripes parallel to the incident polarization possess higher intensity than those diffracted from orthogonal stripes, stemming from the optical anisotropy of the LCs and the periodic lying-helix structure inside the CLC grating [16,36,37]. Besides checkerboard hierarchical gratings, more complex and photo-responsive CLC hierarchical gratings are fabricated by rationally designing the alignments.…”

Section: Resultsmentioning

confidence: 99%

Light-Driven Pitch Tuning of Self-Assembled Hierarchical Gratings

Liu

et al. 2021

Crystals

View full text Add to dashboard Cite

Gratings are of vital importance in modern optics. Self-assembled cholesteric liquid crystal (CLC) gratings have attracted intensive attention due to their easy fabrication and broad applications. However, simultaneously achieving arbitrary patterning and delicate tuning of CLC gratings remains elusive. Here, light-driven pitch tuning is accomplished in hierarchical gratings formed in a molecular switch doped CLC. We fabricate a checkerboard hierarchical CLC grating for a demonstration, whose pitch is optically tuned from 4.6 µm to 10.7 µm. Correspondingly, the first-order diffraction angle continuously changes from 9.4° to 4.8° and a significant polarization selectivity is also observed. In addition, hierarchical CLC gratings with triangular wave pattern, Archimedean spiral, and radial stripes are also demonstrated. This work creates new opportunities for soft-matter-based intelligent functional materials and advanced photonic devices.

show abstract

“…It has been observed that not only electric field but also light is capable of generating periodic patterns in CLCs doped with photoresponsive dyes . Hung et al prepared transmission gratings by applying electric field to a planar aligned CLC and probed their characteristics by monochromatic radiation with wavelengths spanning across the visible spectrum …”

Section: Control Of the Helical Axis Of Clcs By Different Stimulimentioning

confidence: 99%

Stimuli‐Driven Control of the Helical Axis of Self‐Organized Soft Helical Superstructures

2018

View full text Add to dashboard Cite

Supramolecular and macromolecular functional helical superstructures are ubiquitous in nature and display an impressive catalog of intriguing and elegant properties and performances. In materials science, self-organized soft helical superstructures, i.e., cholesteric liquid crystals (CLCs), serve as model systems toward the understanding of morphology- and orientation-dependent properties of supramolecular dynamic helical architectures and their potential for technological applications. Moreover, most of the fascinating device applications of CLCs are primarily determined by different orientations of the helical axis. Here, the control of the helical axis orientation of CLCs and its dynamic switching in two and three dimensions using different external stimuli are summarized. Electric-field-, magnetic-field-, and light-irradiation-driven orientation control and reorientation of the helical axis of CLCs are described and highlighted. Different techniques and strategies developed to achieve a uniform lying helix structure are explored. Helical axis control in recently developed heliconical cholesteric systems is examined. The control of the helical axis orientation in spherical geometries such as microdroplets and microshells fabricated from these enticing photonic fluids is also explored. Future challenges and opportunities in this exciting area involving anisotropic chiral liquids are then discussed.

show abstract

Diffraction of cholesteric liquid crystal gratings probed by monochromatic light from 450 to 750 nm

Cited by 8 publications

References 21 publications

Light-Driven Rotation and Pitch Tuning of Self-Organized Cholesteric Gratings Formed in a Semi-Free Film

Light-Driven Rotation and Pitch Tuning of Self-Organized Cholesteric Gratings Formed in a Semi-Free Film

Light-Driven Pitch Tuning of Self-Assembled Hierarchical Gratings

Stimuli‐Driven Control of the Helical Axis of Self‐Organized Soft Helical Superstructures

Contact Info

Product

Resources

About