Generation of 3-dimensional polymer structures in liquid crystalline devices using direct laser writing

Tartan, CC; Salter, P S; Wilkinson, Timothy D.; Booth, M. J.; Morris, Suzanne M.; Elston, Steve J.

doi:10.1039/c6ra25091b

Cited by 34 publications

(30 citation statements)

References 21 publications

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“…By now, DLW on LC elastomers or networks have accomplished light-activated micro-walkers [113], micro-hand [114], micro-actuator with non-reciprocal motion [115], suspended micromembranes [116], and light-controlled 2D grating [117], photonic circuits [118], elastic microcavities [119], etc. Other attempts on photoresist materials development and writing condition discussion promote the combination of TPP with LCs further [120][121][122].…”

Section: Direct-laser Writing On Liquid-crystal Monomersmentioning

confidence: 99%

Novel liquid crystal photonic devices enabled by two-photon polymerization [Invited]

He¹,

Tan²,

Chanda³

et al. 2019

Opt. Express

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In addition to displays, liquid crystals (LCs) have also found widespread applications in photonic devices, such as adaptive lens, adaptive optics, and sensors, because of their responses to electric field, temperature, and light. As the fabrication technique advances, more sophisticated devices can be designed and created. In this review, we report recent advances of two-photon polymerization-based direct-laser writing enabled LC devices. Firstly, we describe the basic working principle of two-photon polymerization. With this powerful fabrication technique, we can generate anchoring energy by surface morphology to align LC directors on different form factors. To prove this concept, we demonstrate LC alignment on planar, curvilinear surfaces as well as in three-dimensional volumes. Based on the results, we further propose a novel, ultra-broadband, twisted-nematic diffractive waveplate that can potentially be fulfilled by this technique. Next, we briefly discuss the current status of direct-laser writing on LC reactive mesogens and its potential applications. Finally, we present two design challenges: fabrication yield and polymer relaxation/deformation, remaining to be overcome.

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Section: Direct-laser Writing On Liquid-crystal Monomersmentioning

confidence: 99%

Novel liquid crystal photonic devices enabled by two-photon polymerization [Invited]

He¹,

Tan²,

Chanda³

et al. 2019

Opt. Express

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“…The initial alignment of NLC-based photoresists can be achieved using a previously printed template, [169][170][171] along rubbing direction, 172 under the influence of an external magnetic field, 173 or under the influence of an external electric field 174,175 . Furthermore, crosslinking of the monomeric functional groups was shown to efficiently freeze the alignment observed in the photoresist.…”

Section: Liquid Crystalline Materialsmentioning

confidence: 99%

“…Hence, the authors could tune the wavelength selectivity of the proposed WGMR by up to -3.7 nm and +11.5 nm for the first and the second design, respectively E7, 186,187 supplied by Merck® is a well-known NLC mixture that has been broadly used by the scientific community. Noticeably, the group of Elston 174,175,188,189 investigated its use for 3D laser lithography. In the context of light-triggered AM, E7 is generally used together with one or several reactive mesogen(s), such as RM257 mentioned previously, responsible for crosslinking.…”

Section: Wiersmamentioning

confidence: 99%

Hierarchical ordering in light-triggered additive manufacturing

Monti

Blasco

2020

Polym. Chem.

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“…This of course is limited to the creation of planar films. Analogue to isotropic resins, direct writing processes can be used to produce structured films but these techniques are in general slow and therefore not suitable for high volume production. Further, as the polymerization of RMs relies on acrylate groups, the processing has to be performed in an oxygen‐free atmosphere to avoid inhibition of the cure.…”

Section: Introductionmentioning

confidence: 99%

Embossing Reactive Mesogens: A Facile Approach to Polarization‐Independent Liquid Crystal Devices

Wahle

Snow

Sargent

et al. 2018

Advanced Optical Materials

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Reactive mesogens (RMs) are used in a wide variety of applications, from retardation plates for organic light‐emitting display screens, liquid crystal phase stabilization, optical or electrically active elastomers to novel optic components. They can be processed as standard liquid crystals and subsequently polymerized to stabilize both shape and anisotropic properties. However, creating complex shapes while maintaining good alignment of the RM optical axis can be a challenge. In the present work, embossing is used to replicate a wide variety of RM structures in several electro‐optic devices. A novel device geometry is proposed where a polarization‐independent lens is formed by opposing birefringent Fresnel zone plates embossed in aligned RM. The RM forms the optical elements and alignment layers for an index‐matched liquid crystal, arranged to produce the twisted nematic configuration. Low voltages switch the device between nonfocusing and focusing states. After characterizing lens efficiency and beam properties, the method is used to fabricate a switchable multilevel Fresnel zone plate with optical efficiencies beyond 50%, and theoretically able to produce polarization‐independent lenses with efficiencies approaching 100% from a single structure. Finally, manufactured polarization‐independent gratings and microlens arrays are presented using the method to illustrate the wide range of applicability.

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Generation of 3-dimensional polymer structures in liquid crystalline devices using direct laser writing

Abstract: We demonstrate laser writing of birefringent polymer structures with a controllable orientation of the optic axis in liquid crystal devices.

Cited by 34 publications

References 21 publications

Novel liquid crystal photonic devices enabled by two-photon polymerization [Invited]

Novel liquid crystal photonic devices enabled by two-photon polymerization [Invited]

Hierarchical ordering in light-triggered additive manufacturing

Embossing Reactive Mesogens: A Facile Approach to Polarization‐Independent Liquid Crystal Devices

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