Polarisation-sensitive optical elements in azobenzene polyesters and peptides

Ramanujam, P. S.; Dam-Hansen, Carsten; Berg, Rolf H.; Hvilsted, Søren; Nikolova, L.

doi:10.1016/j.optlaseng.2005.06.015

Cited by 33 publications

(17 citation statements)

References 18 publications

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“…At least three degrees of freedom are needed to record an arbitrary GPH, two for the spatial scanning and one for control of the anisotropy orientation. Most of the previously studied scanning methods employ only two, typically one spatial and one orientational [26,[39][40][41]. Of the prior scanning methods that use three degrees of freedom [18,29,42], all employ a pixel-by-pixel discrete scan approach, a beam size not greater than those pixels, and one-shot exposure in each pixel, which altogether make smoothly varying and continuous phase profiles unattainable.…”

Section: B Direct-write Approachmentioning

confidence: 99%

Fabrication of ideal geometric-phase holograms with arbitrary wavefronts

Kim

Liu

Miskiewicz

et al. 2015

Optica

348

251

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Throughout optics and photonics, phase is normally controlled via an optical path difference. Although much less common, an alternative means for phase control exists: a geometric phase (GP) shift occurring when a light wave is transformed through one parameter space, e.g., polarization, in such a way as to create a change in a second parameter, e.g., phase. In thin films and surfaces where only the GP varies spatially-which may be called GP holograms (GPHs)-the phase profile of nearly any (physical or virtual) object can in principle be embodied as an inhomogeneous anisotropy manifesting exceptional diffraction and polarization behavior. Pure GP elements have had poor efficiency and utility up to now, except in isolated cases, due to the lack of fabrication techniques producing elements with an arbitrary spatially varying GP shift at visible and near-infrared wavelengths. Here, we describe two methods to create high-fidelity GPHs, one interferometric and another direct-write, capable of recording the wavefront of nearly any physical or virtual object. We employ photoaligned liquid crystals to record the patterns as an inhomogeneous optical axis profile in thin films with a few μm thickness. We report on eight representative examples, including a GP lens with F/2.3 (at 633 nm) and 99% diffraction efficiency across visible wavelengths, and several GP vortex phase plates with excellent modal purity and remarkably small central defect size (e.g., 0.7 and 7 μm for topological charges of 1 and 8, respectively). We also report on a GP Fourier hologram, a fan-out grid with dozens of far-field spots, and an elaborate phase profile, which showed excellent fidelity and very low leakage wave transmittance and haze. Together, these techniques are the first practical bases for arbitrary GPHs with essentially no loss, high phase gradients (∼rad∕μm), novel polarization functionality, and broadband behavior.

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Section: B Direct-write Approachmentioning

confidence: 99%

Fabrication of ideal geometric-phase holograms with arbitrary wavefronts

Kim

Liu

Miskiewicz

et al. 2015

Optica

348

251

View full text Add to dashboard Cite

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“…This effect, known also as Angular Hole Burning (AHB) results on a macroscopic level formation of significant photoinduced anisotropy -birefringence and dichroism. Based on this unique property of the azobenzene-containing materials, they have been used for numerous applications -most often for reversible optical data storage [2][3][4] , tunable surface relief gratings [5][6][7] or diffractive optical elements with unique polarization properties [8][9][10] . The research on azopolymers during the last decades is also described in some milestone reviews [11][12][13] .…”

Section: Introductionmentioning

confidence: 99%

Diffraction efficiency of polarization holographic gratings recorded in azopolymer thin films coated using different solvents

Blagoeva

Nedelchev

Mateev

et al. 2020

Photosensitive Materials and Their Applications

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We present a study of the diffraction efficiencies of polarization holographic gratings recorded in thin films of the azopolymer PAZO (poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt]). Two series of layers have been prepared using two different solvents-distilled water and methanol. The gratings are inscribed by two plain waves with orthogonal circular polarizations (left and right circular) from a He-Cd gas laser (442 nm) at recording angle 20°, corresponding to grating period 1.3 µm. Higher diffraction efficiency is obtained for the thin film samples spin-coated from the methanol solution for thicknesses below 600 nm. Diffraction efficiency higher than 27% was achieved, as well as surface relief height more than 500 nm.

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“…Thanks to this important property, LC MAs with planar geometries have been produced through the gradient index refraction (GRIN) modulation [16]. Recent studies have shown that GRIN can be created in birefringent materials through polarization holography [17,18].…”

Section: Introductionmentioning

confidence: 99%

Liquid crystal microlens arrays recorded by polarization holography

et al. 2015

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We report the characterization of diffractive microlens arrays (MAs) using a polarization holographic approach assisted by a spatial light modulator (SLM), in a nematic liquid crystal (NLC) cell. The MAs were recorded in the photoaligning substrates of the cell and then replicated in the NLC bulk, through the surface interactions. The transparency of the NLC on a wide range of wavelengths and the ability to tune its optical birefringence, through an external voltage, allowed us to create MAs with high efficiency. We have presented the results obtained for diverse MAs configurations, composed by spherical and cylindrical microlenses and characterized by different focal lengths. The efficiency reaches a value of 90%, at a wavelength of 633 nm.

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Polarisation-sensitive optical elements in azobenzene polyesters and peptides

Cited by 33 publications

References 18 publications

Fabrication of ideal geometric-phase holograms with arbitrary wavefronts

Fabrication of ideal geometric-phase holograms with arbitrary wavefronts

Diffraction efficiency of polarization holographic gratings recorded in azopolymer thin films coated using different solvents

Liquid crystal microlens arrays recorded by polarization holography

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