Ultrafast all-optical switching with photonic nanojets and semiconductor nanoparticles

Abstract

The potential of terabit-per-second fibre optics can be unlocked with emerging all-optical networks and processors employing all-optical switching. To be effective, all-optical switching must support operations with femtojoule switching energies and femtosecond switching times. With this in mind, this work studies geometrical and material characteristics for all-optical switching and develops a new all-optical switching architecture. A nanojet focal geometry is applied, in the form of dielectric spheres, to direct high-intensity photonic nanojets into peripheral semiconductors. Theoretical and experimental analyses demonstrate photonic nanojets, enabling femtojoule switching energies through localized photoinjection, and semiconductor nanoparticles, enabling femtosecond switching times through localized recombination.

An investigation of semiconductor nanoparticles for application to all-optical switching

“…Large spheres, made with contemporary glasses, conform to the thick lens formula, and it can be shown [12] that the highest intensity on the rear surface of the sphere is realized with a refractive index of ≈ 2. Small spheres, that have sizes comparable to the wavelength, require threedimensional electromagnetic analysis.…”