METHOD FOR MEASURING OPTICAL NONLINEARITY OF TWO-DIMENSIONAL MATERIAL

摘要

The method for measuring optical nonlinearity according to the present disclosure comprises utilizing photon pair generation by a spontaneous four-wave light mixing process to observe a photon pair using an optical waveguide in which a two-dimensional material is loaded. Compared with the Z-scan method, the effect of free carriers on the nonlinear refractive index remains indirect. With the length of the loaded two-dimensional material in the optical waveguide direction as a parameter, the theoretical value of the coincidence factor of a photon pair based on coupled wave equations is fitted to the measured value of the coincidence factor of the photon pair. Regarding the coincidence factor of the photon pair, the theoretical value based on coupled wave equations is adjusted to the measured value in a state that reflects the structure of the optical waveguide in which the two-dimensional material is loaded, and the corresponding nonlinear coefficients γ1 and γ2 are then determined.