Gaussian diffraction model for Sb thin films in super-resolution near-field structure

摘要

According to the change of refractive index of Sb thin film with temperature and the radial distribution of temperature within the spot, we can consider the spot irradiated by a Gaussian beam as a phase-modulated screen. Based on Fresnel-kirchhoff diffraction theory, a Gaussian diffraction model which can compute the intensity from far field has been set up. Using this model we can study the nonlinear change of mask layer samples induced by different reasons. A numerical calculation of the transmittance through an Sb-type super-resolution near-field structure was carried out as an example. The Gaussian diffraction model, which is similar to the far field detection process in the optical disk system, is very useful for analyzing the photothermal-induced local structure change of thin films in phase-change and super-resolution optical disks.