Preparation Of Nanoparticle Self-assembled Lenses And Their Application In Super-resolution Optical Microscopy Imaging

The optical microscope uses an optical lens system and visible light to achieve magnification and imaging of small target objects.However,due to the constraints of the diffraction characteristics of light,the highest imaging resolution of a conventional optical microscope can only reach about 200 nm,which increasingly difficult to meet people’s demand for finer microscopic observation.This article uses a self-assembly method of nanoparticles to assemble 15 nm TiO₂nanoparticles and SiO₂nanoparticles with low absorption loss and deep sub-wavelength scale into a hemispherical solid immersion lens（SIL）and a cracked film-type flat superlens,respectively.By achieving near-field optical coupling effect through closely-packed nanostructures,the optical diffraction limit is broken through,and super-resolution optical microscopy imaging is achieved.The super-resolution imaging ability,mechanism,and application are thoroughly investigated.The research content of this article mainly includes the following two aspects:（1）Assembly of high refractive index TiO₂SIL by the silicon oil two-step dehydration method for super-resolution optical microscopy imaging and its application research15 nm anatase TiO₂nanoparticles with high refractive index,low optical absorption loss,and deep sub-wavelength scale are assembled into a high refractive index,controllable width,sub-millimeter solid-state SIL with high visible light transmittance using the silicon oil two-step dehydration process,which is used to achieve 150 nm super-resolution optical microscopy imaging under white light illumination.The assembly process and mechanism of the TiO₂SIL prepared by the silicon oil two-step dehydration method are experimentally studied.In addition,various parameters affecting the imaging magnification and imaging field of view the SIL are studied,and the imaging resolution of the SIL is characterized.At the same time,we have extended the applications of the TiO₂SIL.By using the TiO₂SIL under the objective lens of an optical microscope,the micro-structure of designated regions of samples,such as nanomaterials,cancer cell histopathology staining slides,living cells or bacteria,can be observed with a large field of view,real-time,and high contrast super-resolution magnification,which is fast,accurate,non-destructive and repeatable.Additionally,we have established an optical model and employed optical simulation software to explore the super-resolution imaging mechanism of the TiO₂SIL.This approach offers theoretical support in enabling the TiO₂SIL to achieve high-quality imaging results.（2）Assembly of SiO₂cracked film-type flat superlens by spin coating method for full field-of-view super-resolution optical microscopy imagingAn aqueous dispersion containing 15 nm SiO₂nanoparticles is dropped on the surface of the sample to be observed,and the SiO₂nanoparticles are assembled on the sample surface by spin-coating method into a cracked film-type flat superlens with natural drying cracks.The super-resolution imaging performance of the SiO₂cracked film on the sample（such as a pattern of 100 nm spacing on a Blu-ray disc surface）is studied under an optical microscope with white-light illumination.The experimental parameters affecting the morphology and structure of the SiO₂cracked film,such as the solid content of the SiO₂nanoparticle aqueous dispersion and the spin-coating temperature,are studied.In addition,the super-resolution imaging mechanism and the application potential of the SiO₂cracked film-type flat superlens are also investigated.This study addresses the application bottlenecks of current near-field super-resolution imaging techniques,including high optical absorption loss,limited imaging field of view,and low scanning imaging efficiency.It provides a convenient,practical,efficient,full field of view,and real-time near-field super-resolution optical microscopy imaging technique.