A strong medium is shown in Figure 1c. BaTiO3 microspheres having a refractive index of 1.9 have been self-assembled and distributed on liquid polydimethylsiloxane (PDMS). Just after drying as well as other methods to form PDMS films, the films embedded with microspheres were placed on the sample, and an illumination source of 550 nm was passed by way of the film to kind a magnified virtual image below the specimen in the reflection illumination mode having a resolution of as much as /4. General, microspheres with low refractive index can be directly imaged in air medium, and microspheres with higher refractive index can be imaged at super-resolution in liquid and solid media. The microspheres within the liquid are flexible and can be trapped and manipulated together with the assistance of auxiliary tools, which include optical fibers, to realize the imaging and CFT8634 MedChemExpress sensing of distinct particles and positions. The microspheres within the film is often prepared ahead of time and utilised as a cover glass for the sample, which can stay clear of the evaporation of liquid inside the experiment and strengthen the stability of imaging.Photonics 2021, eight, 434 Photonics 2021, 8, x FOR PEER REVIEW4 of 22 four ofFigure 1. Schematic diagram of distinct Methyl jasmonate Protocol microsphere superlens experimental setups. Schematic diFigure 1. Schematic diagram of different microsphere superlens experimental setups. Schematic diaagrams the device with microspheres in an an (a) air medium, (b) liquid medium, and (c) solid megrams ofof the device with microspheres in(a) air medium, (b) liquid medium, and (c) strong medium. dium.2.2. Principles of Photonic Nanojets for Optical Trapping, Sensing and Imaging two.2. Principles of properties in the photonic nanojets [65], whispering gallery mode [66], and the optical Photonic Nanojets for Optical Trapping, Sensing and ImagingThe optical properties of the photonic nanojets [65], whispering amongst photons directional antenna [67] on the microsphere lens enhance the interactiongallery mode [66], and matter, thereby improving the microsphere lens trapping, sensing, and imaging. phoand directional antenna [67] with the potential of optical improve the interaction involving The imaging of a traditional optical microscope comprises light spots formed andlight and tons and matter, thereby enhancing the capability of optical trapping, sensing, by imaging. dark imaging of a conventional optical microscope comprises light spots diffracted light The streaks. When two objects that happen to be close pass by way of the lens, the formed by light spotsdark streaks. When two objects which are close pass through the lens, standard and will overlap and be indistinguishable. As a result, the resolution on the diffracted optical microscope depends be indistinguishable. For that reason, thefocusing the incident light light spots will overlap and around the size with the spot produced by resolution of standard around the far field, which can be restricted by diffraction. For particle scales lessthe incident light optical microscope will depend on the size in the spot made by focusing than one-tenth of athe far field, which is limited by diffraction. For particle scales significantly less than one-tenth the on wavelength, the scattered light intensity in each and every direction of the particle isn’t of a exact same and is prone to Rayleigh scattering;in each direction of the particle will not be with the wavelength, the scattered light intensity the scattering cross section increases precisely the same refractive index,Rayleigh electric field intensity increasessection increases together with the refracand is prone to plus the scatteri.