Photo-induced bending of chalcogenide glass fiber

Optical fibers of a typical chalcogenide glass, As2S3, can be sharply bent only by sideward irradiation of polarized light. The bending direction depends on the polarization; the fiber bends in the forward/backward directions of light propagation for bandgap light that is linearly-polarized orthogonal/parallel to the fiber axis. A reciprocity law between the intensity and the exposure time holds, which suggests that thermal effects are irrelevant. Alternatively, the bending appears to arise from photo-induced optomechanical forces and fluidity. This phenomenon could be developed to a photo-manipulation method of chalcogenide-glass fibers, promising for all-optical switching/modulation devices working at infrared wavelengths.