Fem simulation to understand parameters controlling photonic nanojet spot size

The diffraction limit in optical microscopy was identified 150 years ago, especially in the far field due to the loss of evanescent signals that contains the high spatial data of the specimen. In recent years, much research on integration of microspheres in optical microscopy have been widely studied to tackle this barrier. In this paper, a 2D FEM simulation study was performed to identify the parameters that assist in achieving a sub-wavelength photonic nanojet using different designs of microsphere geometries. The Full width at half Maximum (FWHM) latitudinal and longitudinal dimensions of the photonic nanojet was numerically calculated and are presented in detail. From the simulations, photonic nanojets with a width as small as 248nm, and elongated photonic nanojets of about 27391nm (25λ) can be achieved. This simple approach can be used in biomedical microscopy which desires fine resolution of nanoscale specimens.Bachelor of Engineering (Chemical and Biomolecular Engineering