Theoretical and experimental analysis on photothermal gratings in guest-host liquid crystal film

Holographic grating originating from photothermal effects in guest-host liquid crystals was characterized using heat-conduction analysis and Fraunhofer’s diffraction theory. The refractive index distributions, which are caused by interference light illumination and photothermal optical nonlinearity, were determined by solving the heat-conduction equation numerically. The diffraction efficiencies, including the dependence of the sample temperature and the grating spacing, were determined from the diffraction theory, and those values showed good quantitative agreement with the experimental values.