Micropatterning of light-sensitive liquid-crystal elastomers

Devetak, Miha; Zupančič, Borut; Lebar, Andrija; Umek, Polona; Zalar, Boštjan; Domenici, Valentina; Ambrožić, Gabriela; Žigon, Majda; Čopič, Martin; Drevenšek‐Olenik, Irena

doi:10.1103/physreve.80.050701

Cited by 26 publications

(19 citation statements)

References 16 publications

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“…It is noteworthy that the VDGs presented here are sufficiently simpler in terms of materials comparing with elastic HPDLCs 19 and azobenzenecontaining liquid crystalline elastomers. 20a, 32,33 In the terms of the gratings performances we can sign out the following advantages of our elastic VDGs: higher efficiency (up to $100% in one order); higher spatial resolution (of about 140 nm for the reection gratings, as will be demonstrated below); higher fully reversible tunability (more than 100%, depending on the used elastomer); no degradation of the grating performances at elevated temperatures and non-sensitivity to light polarization. Comparing with alternative methods for the production of elastic gratings, e.g.…”

Section: Performances Of Elastic Vdgs Under External Strainmentioning

confidence: 92%

Conventional elastomers doped with benzophenone derivatives as effective media for all-optical fabrication of tunable diffraction elements

2016

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Simple and effective approach for the fabrication of volume diffraction gratings (VDGs) using different widely used elastic materials is demonstrated for the first time. The method consists in the introduction of UV-photoactive compounds into the ready-to-use elastomeric films with following gratings inscription by a holographic technique. As photoactive dopants a number of methyl-substituted benzophenone derivatives have been tested. Polydimethylsiloxane- and acrylate-based elastic polymers as well as styrene-ethylene-co-butylene-styrene copolymer are exploited as elastomeric matrices. The diffraction gratings of different geometrical parameters are successfully fabricated in all developed elastic materials. The highest value of the refractive index modulation of about 1 × 10−3 is achieved. The technique enables to create also slanted gratings and multiple gratings. The use of such gratings as strain-controllable elements for managing of light is demonstrated. Moreover, elastic reflection gratings have been produced for the first time using conventional polydimethylsiloxane (PDMS) material. The proposed approach provides a very flexible, low-cost and effective tool for all-optical fabrication of complex diffraction structures in the broad class of commercially available elastomeric materials that undoubtedly gives a strong impact to the field of soft tunable optics, photonics, and spectroscopy

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Section: Performances Of Elastic Vdgs Under External Strainmentioning

confidence: 92%

Conventional elastomers doped with benzophenone derivatives as effective media for all-optical fabrication of tunable diffraction elements

2016

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“…The average power density of UV radiation on the sample during the recording process was ~20 mW/cm 2 , and the typical illumination time was several minutes. In the two-beam configuration, the intensity pattern is described as [7]:…”

Section: Methodsmentioning

confidence: 99%

“…As optical holographic materials, they show many intriguing properties. For instance, they exhibit recording sensitivity that is several orders of magnitude larger than conventional (non-liquid crystalline) elastomers containing similar photoisomerizable moieties [4][5][6][7][8][9]. The recording process takes place in a very nonlinear manner that allows an intricate control over the spatial structuring of the refractive index modulation.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Manipulation of Diffractive Properties of Optical Holographic Gratings from Liquid Crystalline Elastomers

Bošnjaković

Gregorc

et al. 2018

Applied Sciences

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An appealing property of optical diffractive structures from elastomeric materials is a possibility to regulate their optical patterns and consequently also their diffractive features with mechanical straining. We investigated the effect of strain on diffraction characteristics of holographic gratings recorded in a monodomain side-chain liquid crystalline elastomer. The strain was imposed either parallel or perpendicular to the initial alignment direction of the material. At temperatures far below the nematic-paranematic phase transition, straining along the initial alignment affects mainly the diffraction pattern, while the diffraction efficiency remains almost constant. In contrast, at temperatures close to the nematic-paranematic phase transition, the diffraction efficiency is also significantly affected. Straining in the direction perpendicular to the initial alignment strongly and diversely influences both the diffraction pattern and the diffraction efficiency. The difference between the two cases is attributed to shear-stripe domains, which form only during straining perpendicular to the initial alignment and cause optical diffraction that competes with the diffraction from the holographic grating structure.

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“…For instance, the incorporation of azobenzene derivatives as dopants [10], chemically bonded pendant units [11], as well as photo-crosslinkers [12,13] into liquid crystalline polymers [14] and elastomers [15] has been widely explored with the purpose to enhance existing material properties or to enable new effects. Examples include the photo-induced alignment [16] and photo-induced optical anisotropy [17], the light-induced nanopatterning and nanowriting [18] and various properties related to optical and holographic applications [19,20,21,22].…”

Section: Introductionmentioning

confidence: 99%

“…These two molecules are basic components of liquid crystalline elastomers having optical properties [19][20][21][22]23]. The mesomorphic behaviour and self-assembling properties of the binary system, by varying the relative percentage of the two compounds, J7 and M11, were studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM).…”

Section: Introductionmentioning

confidence: 99%

Chemical-Physical Characterization of a Binary Mixture Made of a Photosensitive Azobenzene Derivative and a Smectogen

Borello

Cifelli

Duce

et al. 2015

Molecular Crystals and Liquid Crystals

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We present the characterization of new binary mixtures made of two rod-like molecules: a photosensitive azobenzene derivative (called J7) and a smectogen (called M11). The interest in these two specific compounds is related to their use as basic constituents of photo-active liquid crystalline elastomers and their opto-mechanic applications. Differential scanning calorimetry and polarized optical microscopy were used to characterize the phase diagram of the binary system J7-M11. 2H NMR spectroscopy of the 2H-selectively labelled M11, either alone or as a probe in binary mixtures containing different ratios J7/M11, was applied to study the orientational ordering properties

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Micropatterning of light-sensitive liquid-crystal elastomers

Cited by 26 publications

References 16 publications

Conventional elastomers doped with benzophenone derivatives as effective media for all-optical fabrication of tunable diffraction elements

Conventional elastomers doped with benzophenone derivatives as effective media for all-optical fabrication of tunable diffraction elements

Mechanical Manipulation of Diffractive Properties of Optical Holographic Gratings from Liquid Crystalline Elastomers

Chemical-Physical Characterization of a Binary Mixture Made of a Photosensitive Azobenzene Derivative and a Smectogen

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