Special Issue "Micro and Nano Patterned Substrates for Liquid Crystal Alignment"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Liquid Crystals".

Deadline for manuscript submissions: closed (20 September 2017)

Special Issue Editor

Guest Editor
Prof. Dr. Vladimir Chigrinov

Department of Electronic & Computer Engineering, Hong Kong University of Science and Technology, Hong Kong
E-Mail
Interests: computer modeling of various electrooptical effects in Liquid Crystals (LC); photo-aligning technique for LCD applications; LC devices in fiber optics; fast multistable ferroelectric liquid crystal devices

Special Issue Information

Dear Colleagues,

A new Liquid Crystals section has been established in the open access journal Crystals (http://www.mdpi.com/journal/crystals/sections/liquid_crystals). Because of the many advances in recent years, we are dedicating the first Special Issue of the Liquid Crystals section to the topic “Micro and Nano Patterned Substrates for Liquid Crystal Alignment”. The Special Issue will explore techniques and challenges for micro- and nanopatterned substrates, scientific consequences of the patterns, and technological outcomes. It is intended that both extant and novel methods will be covered, ranging from traditional mechanical techniques adapted to small patterns, to optical techniques, to methods involving non-traditional alignment layers, such as graphene. The goal is to facilitate dissemination of information on methods and outcomes that will benefit the broader community involved in control of liquid crystal alignment.

Prof. Dr. Vladimir Chigrinov
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • alignment layer materials
  • patterned photoalignment
  • mechanically-generated patterns
  • electron and ion beam patterning
  • novel materials and approaches
  • scientific and technological outcomes

Published Papers (5 papers)

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Research

Open AccessArticle Ultrafast Photoalignment: Recording a Lens in a Nanosecond
Crystals 2017, 7(11), 338; doi:10.3390/cryst7110338
Received: 9 October 2017 / Revised: 31 October 2017 / Accepted: 31 October 2017 / Published: 3 November 2017
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Abstract
Liquid crystals can be photoaligned with a single nanosecond pulse acting on thin photoanisotropic coatings on the cell substrates. This phenomenon was demonstrated for pulses of 532 nm and 355 nm wavelengths (second and the third harmonics of a Nd:YAG laser). Direct printing
[...] Read more.
Liquid crystals can be photoaligned with a single nanosecond pulse acting on thin photoanisotropic coatings on the cell substrates. This phenomenon was demonstrated for pulses of 532 nm and 355 nm wavelengths (second and the third harmonics of a Nd:YAG laser). Direct printing of liquid crystal cycloidal diffractive waveplates and diffractive waveplate lenses characterized by high spatial frequencies required only a mJ energy. The liquid crystal alignment dynamics reveal a fast component related to photoalignment of molecules within the photoanisotropic layer and a slower component related to alignment of the liquid crystal within the cell. Full article
(This article belongs to the Special Issue Micro and Nano Patterned Substrates for Liquid Crystal Alignment)
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Open AccessArticle Generating, Separating and Polarizing Terahertz Vortex Beams via Liquid Crystals with Gradient-Rotation Directors
Crystals 2017, 7(10), 314; doi:10.3390/cryst7100314
Received: 20 September 2017 / Revised: 13 October 2017 / Accepted: 15 October 2017 / Published: 18 October 2017
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Abstract
Liquid crystal (LC) is a promising candidate for terahertz (THz) devices. Recently, LC has been introduced to generate THz vortex beams. However, the efficiency is intensely dependent on the incident wavelength, and the transformed THz vortex beam is usually mixed with the residual
[...] Read more.
Liquid crystal (LC) is a promising candidate for terahertz (THz) devices. Recently, LC has been introduced to generate THz vortex beams. However, the efficiency is intensely dependent on the incident wavelength, and the transformed THz vortex beam is usually mixed with the residual component. Thus, a separating process is indispensable. Here, we introduce a gradient blazed phase, and propose a THz LC forked polarization grating that can simultaneously generate and separate pure THz vortices with opposite circular polarization. The specific LC gradient-rotation directors are implemented by a photoalignment technique. The generated THz vortex beams are characterized with a THz imaging system, verifying features of polarization controllability. This work may pave a practical road towards generating, separating and polarizing THz vortex beams, and may prompt applications in THz communications, sensing and imaging. Full article
(This article belongs to the Special Issue Micro and Nano Patterned Substrates for Liquid Crystal Alignment)
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Figure 1

Open AccessArticle Ferroelectric Liquid Crystal Dammann Grating by Patterned Photoalignment
Crystals 2017, 7(3), 79; doi:10.3390/cryst7030079
Received: 20 December 2016 / Accepted: 3 March 2017 / Published: 6 March 2017
Cited by 1 | PDF Full-text (2078 KB) | HTML Full-text | XML Full-text
Abstract
In this article, a ferroelectric liquid crystal (FLC) dammann grating (DG) is demonstrated based on the patterned photoalignment technology. By applying low electric field (10 V) on the FLC DG, the grating can switch between a diffractive state with 7 × 7 optical
[...] Read more.
In this article, a ferroelectric liquid crystal (FLC) dammann grating (DG) is demonstrated based on the patterned photoalignment technology. By applying low electric field (10 V) on the FLC DG, the grating can switch between a diffractive state with 7 × 7 optical spots array and a non-diffractive state, depending on the polarity of electric field. The FLC DG shows very fast switching speed with switching on time and off time to be only 81 μs and 59 μs respectively. Comparing with other fast LC DGs such as the ones based on blue phase LC or dual-frequency LC, the switching speed of the proposed FLC DG is about one order faster, which provides great potential and perspective for the FLC DG to be applied in a broad range of optical applications such as optical communication and beam shaping. Full article
(This article belongs to the Special Issue Micro and Nano Patterned Substrates for Liquid Crystal Alignment)
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Open AccessArticle SRG Inscription in Supramolecular Liquid Crystalline Polymer Film: Replacement of Mesogens
Crystals 2017, 7(2), 52; doi:10.3390/cryst7020052
Received: 16 January 2017 / Revised: 9 February 2017 / Accepted: 9 February 2017 / Published: 11 February 2017
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Abstract
The photoinduced surface relief formation via mass transfer upon irradiation with patterned light has long been a subject of extensive investigation. In azobenzene-containing liquid crystalline materials, UV light irradiation that generates the cis isomer leads to the liquid crystal to isotropic photochemical transition.
[...] Read more.
The photoinduced surface relief formation via mass transfer upon irradiation with patterned light has long been a subject of extensive investigation. In azobenzene-containing liquid crystalline materials, UV light irradiation that generates the cis isomer leads to the liquid crystal to isotropic photochemical transition. Due to this phase change, efficiency of the mass transfer to generate a surface relief grating (SRG) becomes markedly greater. We have previously indicated that azobenzene-colored SRG-inscribed film can be bleached by removing a hydrogen-bonded azobenzene mesogen. However, this process largely reduces the height feature of the SRG corrugation. Herein, we propose an extended procedure where a colorless mesogen is filled successively after the removal of the azobenzene side chain. The process involves four stages: (i) SRG inscription in a hydrogen-bonded supramolecular azobenzene material; (ii) crosslinking (insolubilization) of the SRG film; (iii) removal of azobenzene mesogen by rinsing with a solvent, and (iv) stuffing the hollow film with a different mesogen. Although the final stuffing stage was insufficient at the present stage, this work demonstrates the possibility and validity of the strategy of mesogen replacement. Full article
(This article belongs to the Special Issue Micro and Nano Patterned Substrates for Liquid Crystal Alignment)
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Open AccessArticle Designs of Plasmonic Metamasks for Photopatterning Molecular Orientations in Liquid Crystals
Crystals 2017, 7(1), 8; doi:10.3390/cryst7010008
Received: 15 December 2016 / Revised: 24 December 2016 / Accepted: 26 December 2016 / Published: 30 December 2016
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Abstract
Aligning liquid crystal (LC) molecules into spatially non-uniform orientation patterns is central to the functionalities of many emerging LC devices. Recently, we developed a new projection photopatterning technique by using plasmonic metamasks (PMMs), and demonstrated high-resolution and high-throughput patterning of molecular orientations into
[...] Read more.
Aligning liquid crystal (LC) molecules into spatially non-uniform orientation patterns is central to the functionalities of many emerging LC devices. Recently, we developed a new projection photopatterning technique by using plasmonic metamasks (PMMs), and demonstrated high-resolution and high-throughput patterning of molecular orientations into arbitrary patterns. Here we present comparisons between two different types of metamask designs: one based on curvilinear nanoslits in metal films; the other based on rectangular nanoapertures in metal films. By using numerical simulations and experimental studies, we show that the PMMs based on curvilinear nanoslits exhibit advantages in their broadband and high optical transmission, while face challenges in mask designing for arbitrary molecular orientations. In contrast, the PMMs based on nanoapertures, though limited in optical transmission, present the great advantage of allowing for patterning arbitrary molecular orientation fields. Full article
(This article belongs to the Special Issue Micro and Nano Patterned Substrates for Liquid Crystal Alignment)
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Figure 1

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

 

 

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