Anne-Catherine Etile

Bio: Anne-Catherine Etile is an academic researcher. The author has contributed to research in topics: Polarization (waves) & Linear polarization. The author has an hindex of 3, co-authored 3 publications receiving 83 citations.

Phase-coherent control of the molecular polar order in polymers using dual-frequency interferences between circularly polarized beams

Abstract: Dual-frequency interferences using appropriate combinations of circular writing beam polarizations are demonstrated to enable full control of the molecular polar order in a polymer. A comparative theoretical and experimental analysis of the all-optical poling process in the cases of linear, cohelical, and counterhelical writing polarizations is achieved. Dynamics, efficiency, phase matching, and tensorial aspects are analyzed. Nearly perfect dipolar and octupolar ordering is achieved using conventional one-dimensional molecules. As a feature of dual-frequency holography with circular polarizations, writing beam phase retardation \ensuremath{\Delta}\ensuremath{\Phi} is coded into a ${\ensuremath{\chi}}^{(2)}$ pattern rotation by the same angle. Interestingly, in the case of a fundamental beam with linear polarization, second harmonic generation is independent of the polarization direction.

All‐optical manipulation of azo‐dye molecules

Abstract: A challenging issue in the field of the design of devices for photonic applications is to achieve complete manipulation of the molecular order. Azo-dye aromatic polymers have been shown to offer interesting prospects for material engineering using light matter interactions. Dual-frequency irradiation using appropriate combinations of circular beams polarizations are demonstrated to enable full control of the molecular polar rotation. More recent results on photoinduced surface-relief gratings have also opened the way of molecular translation control using optical fields. Understanding of the relevant parameters of molecular translation processes is a key issue for optimization of such an optomechanical effect : a simple model accounting qualitatively for the essential features of photoinduced surface-relief gratings will be presented.

All-optical poling in polymers: dynamical aspects and perspectives

Abstract: All-optical poling is based on the excitation of nonlinear molecules using dual-frequency beams. The process is optimized at a molecular level when the molecules are resonantly excited. From the point of view of frequency conversion applications, this raises the question of device transparency to the frequency-converted output. In order to treat this efficiency transparency tradeoff, we recently developed a simple model accounting for all the observable parameters. The model permits a good prediction of the poling dynamics. Its self-consistency permits the description of all the known all-optical poling schemes. In particular, analysis of the parameters of the model permits the identification of new strategies towards the realization of stable and transparent phase-matched materials for frequency conversion. Some preliminary experimental results are presented in this respect.

Novel photo-switching using azobenzene functional materials

Abstract: Azobenzene (azo) chromophores have been incorporated into a wide variety of materials and molecular architectures, including polymers, dendrimers, and molecular glasses. Azobenzene exhibits a uniquely clean and efficient photochemistry, with facile geometric isomerization about the azo bond, converting the molecule from trans to cis . This review discusses the extensive number of investigations of azobenzene photo-switching and photo-modulation. In particular, azos can be used to alter material behaviour with light, switching both molecular and macroscopic properties. A large number of photobiological studies have shown that interfacing the azo chromophore with enzymes and biopolymers is feasible and useful. The all-optical surface patterning unique to azobenzenes is also reviewed. Lastly, azobenzene photomechanical effects are discussed.

Patterned piezo-, pyro-, and ferroelectricity of poled polymer electrets

Abstract: Polymers with strong piezo-, pyro-, and ferroelectricity are attractive for a wide range of applications. In particular, semicrystalline ferroelectric polymers are suitable for a large variety of piezo- and pyroelectric transducers or sensors, while amorphous polymers containing chromophore molecules are particularly interesting for photonic devices. Recently, a new class of polymer materials has been added to this family: internally charged cellular space-charge polymer electrets (so-called “ferroelectrets”), whose piezoelectricity can be orders of magnitude higher than that of conventional ferroelectric polymers. Suitable patterning of these materials leads to improved or unusual macroscopic piezo-, pyro-, and ferroelectric or nonlinear optical properties that may be particularly useful for advanced transducer or waveguide applications. In the present paper, the piezo-, pyro-, and ferroelectricity of poled polymers is briefly introduced, an overview on the preparation of polymer electrets with patterned...

From nanoscopic to macroscopic photo-driven motion in azobenzene-containing materials

Abstract: Abstract The illumination of azobenzene molecules with UV/visible light efficiently converts the molecules between trans and cis isomerization states. Isomerization is accompanied by a large photo-induced molecular motion, which is able to significantly affect the physical and chemical properties of the materials in which they are incorporated. In some material systems, the nanoscopic structural movement of the isomerizing azobenzene molecules can be even propagated at macroscopic spatial scales. Reversible large-scale superficial photo-patterning and mechanical photo-actuation are efficiently achieved in azobenzene-containing glassy materials and liquid crystalline elastomers, respectively. This review covers several aspects related to the phenomenology and the applications of the light-driven macroscopic effects observed in these two classes of azomaterials, highlighting many of the possibilities they offer in different fields of science, like photonics, biology, surface engineering and robotics.