title: Direct observation of below-diffraction-limited optical spot induced by nonlinear saturable absorption of Ag-doped Si nanofilms.
abstract: In this work, using the scanning near-field optical fiber probe method, we carry out a direct observation of below-diffraction-limited optical spot induced by nonlinear saturable absorption characteristic of Ag-doped Si nanofilms. The experimental results indicate that the squeezed spot size decreases with laser power increase, and the smallest spot can be squeezed to 68% of the diffraction-limited focusing spot size, which is very useful and can be applied to superresolution optical recording, optical lithography, and optical imaging.
authors.affiliation: Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, No. 390, Qinghe Road, Jiading District, Shanghai 201800, China. weijingsong@siom.ac.cn
authors.forename: Jingsong
authors.initials: J
authors.lastname: Wei
authors.forename: Jing
authors.initials: J
authors.lastname: Liu