Self-induced light polarization rotation in azobenzene-containing polymers

Abstract

We report here a light-induced phenomenon—a self-induced rotation of the azimuth of elliptically polarized light passing through photobirefringent azopolymers. The experiments are carried out with films of amorphous and liquid-crystalline polymers. It has been shown that the induced rotation angle depends on the ellipticity of the input light. A theoretical analysis of the phenomenon has been done and it has been shown that light induces chiral structure in the polymer films.

Chiroptical Molecular Memory of Amorphous Azopolymer using Light Handedness

“…As the ellipticity of the beam increased further, the induced CD became smaller, and when the beam profile approached to circularly polarization state, the CD signal became negligible again. Even though dependence of ellipticity on optical rotation was reported [5], this kind of strong dependence of ellipticity on induced circular dichroism has never been reported before. We are currently investigating the detailed mechanism of this process and the nature of the induced CD.…”

Optical and Physical Applications of Photocontrollable Materials: Azobenzene-Containing and Liquid Crystalline Polymers

“…Photoinduced circular anisotropy was found to depend on the nature of the excitation light (such as its ellipticity, beam intensity, wavelength and irradiation time) [188][189][190][191]. Although the chemical structure of the polymer main-chain employed by each study was different (ester, epoxy, and methacrylate, for example) the proposed mechanism for the generation of the photoinduced chirality was identical.…”

“…Nikolova and coworkers reported that the rotation angle depends on the function Δn·e/(1 − e 2 ) [188]. (Here, the terms "Δn" and "e" represent photoinduced birefringence and ellipticity, respectively.)…”

Azobenzene Polymers for Photonic Applications

“…This reorientation continues throughout the film depth. Overall, a chiral ordering of the chromophore domains is established (Nikolova et al, 2000). Remarkably, one can switch between a right-and left-handed supramolecular helix at will, by changing the incident light handedness.…”