Surface relief grating formation in liquid-crystalline side-chain azopolymers by femtosecond pulse holography

Abstract

Articles you may be interested inDynamic mechanical and thermal behavior of novel liquid-crystalline polybutadiene-diols with azobenzene groups in side chains Biphotonic holographic recording in a liquid crystalline cyanoazobenzene side-chain polymethacrylate. Polarization, intensity, and relief gratings An analysis of the anisotropic and topographic gratings in a side-chain liquid crystalline azobenzene polyester Surface relief gratings were inscribed in the liquid-crystalline side-chain ͑LCSC͒ azopolymers using two-beam interference of near-infrared femtosecond laser pulses. The LCSC azopolymer films were prepared using acrylate-based homo-and copolymers with the azobenzene group in the side chain. The LC properties of the polymers were confirmed by differential scanning calorimetry and optical polarizing microscopy. By adjusting the writing conditions to the optimum fluence, highly efficient gratings were fabricated. This phenomenon is ascribed to a fact that the multiphoton absorption-induced photoisomerization facilitates the parallel ordering of LC mesogenic side groups and the grating formation. Even after the writing beams are removed, the grating relaxation hardly occurs. Such a very slow relaxation might be due to the collective behavior of aligned LC mesogenic side groups in the domain.

Synthesis and Properties of Azo-Based ABC Triblock Copolymers Owning Interaction and Composition Parameters That Influence Their Phase Behaviors

“…The sharp peak at 99 °C (2.6 J/g) corresponds to the transition temperature from smectic-to-nematic phase (T S−N ), while on the contrary the weak peak around 179 °C is designated as the nematic-toisotropic transition temperature (T N−I ). These phase transition behaviors are similar to those observed for azobenzene-based polymers in the literature 69. For PCAEMA-b-PBMA-CTA, only T g and one mesophase temperature (T S−N ) are observed at 47 and 106 °C.…”

Design of Collective Motions from Synthetic Molecular Switches, Rotors, and Motors

“…It is possible to inscribe SRG by using interfering beams at different wavelengths − by adding “assisting beams” to increase the isomerization rate, , by using more than two interfering beams, and even when incoherent light is used. , Some examples used pulsed irradiation. − The interference can also be achieved when light is irradiated through a photomask. − Half-grating spacing has also been achieved by Miniewicz and coworkers when they used an s-/p- interference pattern that they attributed to the interference between the zeroth- and first-order scattered beams. Interestingly, elliptic interference patterns can be used to fabricate asymmetric SRG. − For instance, Kawatsuki et al experimented a variety of polarization interference patterns, and they observed the formation of blazed SRG when two orthogonal elliptically polarized light beams where used (Figure a).…”

Simple Two-Photon Inscription of Surface Relief Gratings with Azobenzene Functionalized Polymer

“…al. reported multi-photon SRG recording on liquid-crystalline side-chain azopolymer thin films under 130 femtosecond laser irradiation (7). SRGs with large modulation depth of 360 nm were fabricated.…”