All-optical switching in azo dye doped liquid crystals based on spatial cross-phase modulation

Two-color all-optical switching is demonstrated in azo dye doped nematic liquid crystals by means of the spatial cross-phase modulation (SXPM) method. A 633 nm light with the power below the diffraction excitation threshold diffracts into concentric rings under the irradiation of a 532 nm light. The ring number and size of the diffraction pattern of the 633 nm light increases with the power of the 532 nm light rising. Taking advantages of the unique physical and optical properties of the liquid crystals, the circular symmetry of the diffraction pattern of the 633 nm is well preserved. It indicates that the irregular and unpredictable distortion of the diffraction pattern caused by the light induced thermal convection could be eliminated, providing potential applications prospect in designing advanced optical devices for all-optical information conversion. In addition, it is found that the SXPM phenomenon between the two lights only happens when the two beams are merged together. Even a small intersection angle between the two lights could change the obtained pattern of the 633 nm light completely. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

Two-color all-optical switching is achieved in azo dye doped nematic liquid crystals through the SXPM method, effectively eliminating irregular distortions caused by light-induced thermal convection. The SXPM phenomenon between the two lights only occurs when they are merged together, with even a small intersection angle completely changing the pattern of the 633 nm light.