High-refractive-index Nanosparticles on Optical Fibres for High-Resolution Lensing Applications

In this work we propose a mechanism to produce high-resolution spatial focusing of electromagnetic waves at telecommunication wavelengths (1550 nm) by using high-refractive index nanoparticles. In this context, we are able to generate photonic nanojets (PNJs) for nearfield focusing by carefully engineering truncated nanospheres placed at the end of an optical fibre. It will be shown how the focal spot (measured at the output surface of the truncated nanosphere) has a high transverse resolution with a Full-Width at Half-Maximum (FWHM) of less than 0.25λ. The proposed dielectric truncated nanosphere-optical fibre structure may be used in applications where high-spatial resolution is needed such as sensing imaging systems.