Extraordinary optical transmission provides a workbench for squeezed light transduction by localized-surface-plasmons. Initial squeezing of 3.5 dB resulted in 1.2-1.4 dB of squeezing after passing through a nanohole-array despite 80% attenuation.
We demonstrate the transduction of macroscopic quantum correlations by Ag localized surface plasmons (LSPs). Quantum noise reduction, or squeezed light, generated through four-wave mixing in Rb vapor, is coupled to a Ag nanohole array designed to exhibit LSP-mediated extraordinary-optical transmission spectrally coincident with the squeezed light source at 795 nm. This first demonstration of the coupling of quantum light into LSPs conserves spatially dependent quantum information, allowing for parallel quantum protocols in on-chip subwavelength quantum information processing.
Surface plasmon resonance (SPR) sensors can reach the quantum noise limit of the optical readout field in various configurations. We demonstrate that two-mode intensity squeezed states produce a further enhancement in sensitivity compared with a classical optical readout when the quantum noise is used to transduce an SPR sensor signal in the Kretschmann configuration. The quantum noise reduction between the twin beams when incident at an angle away from the plasmonic resonance, combined with quantum noise resulting from quantum anticorrelations when on resonance, results in an effective SPR-mediated modulation that yields a measured sensitivity 5 dB better than that with a classical optical readout in this configuration. The theoretical potential of this technique points to resolving particle concentrations with more accuracy than is possible via classical approaches to optical transduction.