DETAILED CHARACTERISTICS OF PHOTOTHERMAL INDEX CHANGE IN GUEST-HOST LIQUID CRYSTALS

Detailed characteristics have been performed for optical nonlinearity originating in photothermal effects in guest-host liquid crystals. The effects of liquid crystal cell parameters and irradiation conditions on photothermal self-phase modulation and the resulting self-diffracted beam characteristics were quantitatively investigated by heat-conduction analysis and Kirchhoff's diffraction theory. We successfully explained all optical phenomena and our experimental and theoretical technique described here was useful for characterizing the photothermal self-phase modulation. This means that the photothermal mechanism was dominant in the laser-induced refractive index change in our guest-host liquid crystal cells and it is expected that our analytical technique described here will be useful for characterizing the extent to which the photothermal refractive-index change affects the laser-induced refractive index change in other kinds of guest-host liquid crystal cells in the future.