Interferometric All-Optical Routing of Upconverted Light by Dielectric Metasurfaces

We propose a dual-beam pumping scheme whereby a pulse of telecom frequency ω (1550 nm wavelength) is mixed with its frequency-doubled replica at 2ω. This brings about sum-frequency generation at ω+2ω = 3ω on top of third harmonic at ω+ω+ω = 3ω. We exploited the diffraction by an AlGaAs metasurface for realizing the symmetry breaking which is key to avoid averaging out the interference between the two coherent frequency-tripling pathways. The upconverted light can thereby be routed into different diffraction orders with high selectivity, based on the pumps’ relative phase, providing a platform for GHz-rate amplitude modulation and information encoding.