Information transfer from the optical phase to a plasmonic digital encoder composed of a gold nanorod pair.

Small all-optical devices are central to the optical computing. Plasmonic digital encoders (PDEs) with a featured dimension of ∼1µm hold the key for transferring information from far field to photonic processing systems. Here we propose a PDE design composed of two gold nanorods (AuNRs), whose pattern represents 2-bit digital information. We implanted information into the spectral phase of a femtosecond pulse by pulse shaping and controlled the two-photon photoluminescence pattern of an AuNR pair. The high contrast ratios were achieved with 13.01 and 6.02 dB for binary codes "1-0" and "0-1", respectively.