Elongated Photonic Nanojets Generated by Spherical Shaped Single Dielectric Core-Shell Microparticles

Theoretical simulations on single dielectric microspherical particles illuminated by plane wave are performed systematically to find out the key parameters for (i) generating elongated photonic nanojet and (ii) obtaining more focal length of the microsphere or working distance. These simulations are performed using analytical theory proposed by Aden and Kerker [1]. In addition, the dependence of the intensity distribution inside and outside the core-shell particles, length and width of the PNJs on the refractive index of the surrounding medium is studied in detail. The difference in the PNJs of the microparticles illuminated with resonant and non-resonant illuminations is also investigated.