Universal soft matter template for photonic applications

Sio, Luciano De; Ferjani, Sameh; Strangi, Giuseppe; Umeton, Cesare; Bartolino, Roberto

doi:10.1039/c1sm05045a

Cited by 35 publications

(20 citation statements)

References 20 publications

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“…This is mainly due to the wide-ranging possibilities for future applications, from volume holographic memory over 3D imaging and waveguides [1][2][3][4], up to optical sensing, photonic circuits and integrated optics [5][6][7]. Photosensitive polymers are of particular interest.…”

Section: Introductionmentioning

confidence: 99%

Spatially Resolved Analysis of Bragg Selectivity

Sabel¹

2015

Applied Sciences

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This paper targets an inherent control of optical shrinkage in photosensitive polymers, contributing by means of spatially resolved analysis of volume holographic phase gratings. Point by point scanning of the local material response to the Gaussian intensity distribution of the recording beams is accomplished. Derived information on the local grating period and grating slant is evaluated by mapping of optical shrinkage in the lateral plane as well as through the depth of the layer. The influence of recording intensity, exposure duration and the material viscosity on the Bragg selectivity is investigated.

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Section: Introductionmentioning

confidence: 99%

Spatially Resolved Analysis of Bragg Selectivity

Sabel¹

2015

Applied Sciences

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“…In fact, we have recently shown [10] that it is possible to realize a polymeric template by etching a periodic liquid crystalline composite material called POLICRYPS (POlymer LIquid CRYstal Polimer Slices), a microcomposite holographic grating made of slices of almost pure polymer alternated to films of well aligned NLC [11][12][13]. In these structures, the NLC can be conveniently removed by using a microfluidic etching process and the obtained polymeric template can be filled, in a second step, with self-organizing materials.…”

Section: /[384]mentioning

confidence: 97%

“…To induce a long range order in the material, we have exploited the universal characteristics of a POLICRYPS-like polymeric microstructure realized according to the technique described in Ref. [10]. By capillary flow, we injected the PLC into the micro-channels of the polymeric template; during the whole filling process the sample was kept at a fixed high temperature (70 • C); this ensured a complete transition to the isotropic state of the LCs.…”

Section: All-optical Diffraction Gratingsmentioning

confidence: 99%

Light Sensitive Liquid Crystals for All-Optical Photonic Devices

Sio

Tedesco

Serak

et al. 2012

Molecular Crystals and Liquid Crystals

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We report our recent efforts on the fabrication and characterization of light responsive devices realized in soft composite materials. Periodic microstructures obtained by means of a photolithographic technique and a chemical etching process have been used to micro confine a light responsive liquid crystal stabilized through a self-organization processes.The high quality, light responsive, periodic microstructures have been exploited for realizing different all-optical, fast and low power applications. An overview of the realized photonic devices is presented.

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“…Holographic gratings in liquid crystals have been studied for their potential use in displays, communications, optical data storages, and other optical applications. − By far, the vast majority of studies involving holographically patterning liquid crystalline materials has either involved a process called POLICRYPS (“POlymer LIquid CRYstal Polymer Slices) − or involved holographic polymer dispersed liquid crystals (also referred to as H-PDLCs). − Both of these processes involve holographically patterning a mixture of nonmesogenic monomer (40–85%), a nonreactive low molecular weight liquid crystal (10–55%), and a photoinitiator (0.1–3%). − Upon holographically patterning the sample, the isotropic monomer will react and concentrate in the regions of high intensity light, and through diffusion, the nonreactive liquid crystal will concentrate and phase separate into discrete domains in the dark regions. The resulting sample will have a significant refractive index modulation between the alternating layers of isotropic solid polymer and layers with anisotropic liquid crystal domains.…”

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confidence: 99%

Reconfigurable Reflective Colors in Holographically Patterned Liquid Crystal Gels

et al. 2020

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Thin film holographic gratings have attracted significant attention due the tailorability of their photonic properties. The ability of holography to create materials with unique photonic properties is particularly promising when combined with stimuliresponsive liquid crystals. Holographic polymer-dispersed liquid crystals (H-PDLCs) are an example of such a system where nonuniform irradiation is used to template alternating polymer-rich and polymer-poor regions with a periodicity related to the illumination wavelength. These systems typically use nonmesogenic monomers at a concentration range where a significant volume fraction of the final system is polymer. Here, we present a reconfigurable material that was generated by holographically polymer stabilizing liquid crystals (H-PSLCs) using liquid crystalline monomers, thereby enabling both alternating regions to be liquid crystalline. The "stabilizing effect" of the liquid crystalline polymer leads to a material with regions of periodic transition temperatures. As written, the polymer-rich regions have a higher isotropic transition temperature than the polymer-poor regions. Upon heating these samples beyond the isotropic temperature of the polymer-poor regions, a vivid wavelength specific reflection appears due to the refractive index mismatch between the ordered liquid crystalline polymer-rich regions and the disordered isotropic polymer-poor regions. When these materials are further heated to the isotropic temperature of the polymer-rich regions, the samples again return to a transparent state because the refractive index modulation between the alternating isotropic regions is negligible. By tailoring the liquid crystalline isotropic transition temperature to be near-room temperature, modest AC-fields can be used as an Ohmic heat source to drive the thermal color change.

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Universal soft matter template for photonic applications

Cited by 35 publications

References 20 publications

Spatially Resolved Analysis of Bragg Selectivity

Spatially Resolved Analysis of Bragg Selectivity

Light Sensitive Liquid Crystals for All-Optical Photonic Devices

Reconfigurable Reflective Colors in Holographically Patterned Liquid Crystal Gels

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