Experimental study on the application of a Fresnel zone plate in a scattering-type scanning near-field optical microscope

Abstract

With the advancement of nano-photonics, near-field optical microscopy technology has gradually attracted widespread attention from researchers in different fields in recent years. In order to address the practicality and integration issues of near-field optical microscopy technology, this paper studies the basic principle and construction scheme of a scattering-type scanning near-field optical microscope (s-SNOM). We designed and built an s-SNOM system that realizes the measurement of impurity particles with a diameter of about 100 nm. The practicality of the system has been experimentally verified. Furthermore, a large ring width amplitude-type Fresnel zone plate (FZP) with a processing error of 100 nm is prepared using UV lithography. Finally, by replacing the focusing lens in the s-SNOM system with the prepared FZP, the recognition of impurity particles with a diameter of about 100 nm can also be achieved. The experimental results indicate that it is possible to achieve the integration of the s-SNOM system without reducing resolution. This study provides a preliminary exploration for the practicality and integration of the SNOM systems.