Memristive Control of Plasmon-Mediated Nonlinear Photoluminescence in Au Nanowires.

Nonlinear photoluminescence (N-PL) is a broadband photon emission arising from a nonequilibrium heated electron distribution generated at the surface of metallic nanostructures by ultrafast pulsed laser illumination. N-PL is sensitive to surface morphology, local electromagnetic field strength, and electronic band structure, making it relevant to probe optically excited nanoscale plasmonic systems. It also has been key to accessing the complex multiscale time dynamics ruling electron thermalization. Here, we show that plasmon-mediated N-PL emitted by a gold nanowire can be modified by an electrical architecture featuring a nanogap. Upon voltage activation, we observe that N-PL becomes dependent on the electrical transport dynamics and can thus be locally modulated. This finding brings an electrical leverage to externally control the photoluminescence generated from metal nanostructures and constitutes an asset for the development of emerging nanoscale interface devices managing photons and electrons.

Coherent two-beam steering of delocalized nonlinear photoluminescence in a plasmon cavity.

We aim at controlling the spatial distribution of nonlinear photoluminescence in a shaped micrometer-size crystalline gold flake. Interestingly, the underlying surface plasmon modal landscape sustained by this mesoscopic structure can be advantageously used to generate nonlinear photoluminescence (nPL) in remote locations away from the excitation spot. By controlling the modal pattern, we show that the delocalized nonlinear photoluminescence intensity can be redistributed spatially. This is first accomplished by changing the polarization orientation of the pulsed laser excitation in order to select a subset of available surface plasmon modes within a continuum. We then propose a second approach to redistribute the nPL within the structure by implementing a phase control of the plasmon interference pattern arising from a coherent two-beam excitation. Control and engineering of the nonlinear photoluminescence spatial extension is a prerequisite for deploying the next generation of plasmonic-enabled integrated devices relying on hot carriers.

Interconnect-Free Multibit Arithmetic and Logic Unit in a Single Reconfigurable 3 µm2 Plasmonic Cavity.

Processing information with conventional integrated circuits remains beset by the interconnect bottleneck: circuits made of smaller active devices need longer and narrower interconnects, which have become the prime source of power dissipation and clock rate saturation. Optical interchip communication provides a fast and energy-saving option that still misses a generic on-chip optical information processing by interconnect-free and reconfigurable Boolean arithmetic logic units (ALU). Considering metal plasmons as a platform with dual optical and electronic compatibilities, we forge interconnect-free, ultracompact plasmonic Boolean logic gates and reconfigure them, at will, into computing ALU without any redesign nor cascaded circuitry. We tailor the plasmon mode landscape of a single 2.6 µm2 planar gold cavity and demonstrate the operation and facile reconfiguration of all 2-input logic gates. The potential for higher complexity of the same logic unit is shown by a multi-input excitation and a phase control to realize an arithmetic 2-bit adder.