Nonlinear optical limiting of the azo dye methyl-red doped nematic liquid crystalline films

We describe the nonlinear optical limiting behaviors of the azo dye methyl-red-doped nematic liquid crystalline (NLC) films and report the phenomena of the formation of an interesting dark spot and a dynamic self-action diffraction ring pattern in the far field beyond the sample cell. We present the method of measuring the optical limiting characteristics of the methyl-red-dye-doped NLC films with typical test results obtained in the experiments. We theoretically analyze the optical limiting mechanisms of the methyl-red-dye-doped NLC films and discuss the advantages and restrictions of the methyl-red dye doped liquid crystal limiters, and propose several possible solutions to overcome these restrictions.