Research On Super-resolution Imaging Characteristics Based On Microsphere Lens

Optical microscopy technology is widely used in the field of micro-nano structure detection,and plays an important role in scientific research and national economy.However,due to the diffraction limit,the resolution of an optical microscope is about half of the wavelength,and its lateral resolution is up to about 200 nm in the visible light band.The superresolution micro-imaging method based on the microsphere lens has the advantages of simplicity,directness,and label-free.Since it was discovered,it has attracted widespread attention from researchers at home and abroad.In this paper,we makes in-depth research on the analysis of microsphere lens super-resolution imaging resolution,the quantification of imaging magnification,the improvement of imaging clarity,and the combination of interference technology to achieve three-dimensional topography measurement.This paper first introduces and explains the magnification and super-resolution effects of microsphere lenses from three directions: geometric optics,evanescent wave transmission,and photon nanojet.Based on the above research,we carry out experiments to study the relationship between the microsphere size and the magnification of the microsphere lens.Through comparative experiments,the effects of imaging methods of microsphere lens,incident light wavelength and film thickness on imaging sharpness are studied.The experimental results are simulated and analyzed in combination with the photon nanojet effect.Experiments and simulations revealed that when melamine formaldehyde resin microspheres with a refractive index of 1.68 and a diameter of 8 μm were immersed in polydimethylsiloxane(PDMS)with a thickness of 1.5 μm under a short wavelength of monochromatic,the focusing effect of the microsphere lens is the best,and the imaging of the microsphere lens is the clearest.To go one step further,from the two-dimensional imaging to the three-dimensional measurement,the measurement method combining microsphere lens super-resolution and interference microscopy technology was studied.By adjusting the relative positions of the reference plate and the beam splitter in the interference objective lens,the optical path difference introduced by the microsphere lens is matched.So we can obtain the interference pattern of the sample after imaging by the microsphere lens.Through the phase shift algorithm and the algorithm to eliminate tilt and curvature,we obtained the three-dimensional topography of the micro-nano structure.Experiments show that microsphere lenses and interference microscopes can achieve three-dimensional topography measurement of smaller samples.