Working mechanism of 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 consider the dynamic optical aperture as a self-focusing thermal lens of Sb thin film in super-resolution near-field structure of SiN/Sb/SiN, and obtain the radius of the dynamic optical aperture (self-focusing thermal lens) 80 nm, the focusing length 22.5 nm, and the diameter of spot through the self-focusing thermal lens 100 nm by setting the Sb thin film thickness 30 nm, laser power 2 mW, and irradiation time on the Sb thin film 1.45 ns. At the same time, the intensity of spot focused by the self-focusing thermal lens of Sb thin films can be greatly enhanced. The working mechanism of Sb thin film in super-resolution near-field structure of SiN/Sb/SiN has been explained.