Photonic Nanojet Properties Of Dielectric Microcylinders

In recent years, it has been demonstrated that micron-scale dielectric spheres and cylinders can form an intense sharply focused photon beam, termed a photonic nanojet. The photonic nanojet effect can be used in a broad range of biomedical and photonics applications, including super-resolution microscopy, optical endoscopy, spectroscopy, and nanolithography. In this work, by means of finite-difference time-domain (FDTD) numerical simulation, we studied the nanojet properties of dielectric microcylinders over a wide range of diameters (4 lambda-20 lambda) and refractive indices (1.5-2.0), where lambda is the wavelength of light. We studied how the nanojet beam size, intensity, and focal distance vary as a function of size and refractive index of the microcylinders, and refractive index contrast between the microcylinders and the background medium surrounding them.