Quantum engineering meets nanoscale data processing: Unleashing the power of light-driven conductivity control

Over the past few decades, the field of data processing and transferring technology has advanced at a rapid pace. This growth can be attributed to Moore's Law, which predicts that the number of transistors on a microchip will double roughly every two years, enabling the semiconductor industry to make electronic devices smaller, faster, and more efficient.

However, electronic interconnections have presented challenges in data transferring due to delays and thermal issues that limit capacity. In an effort to address this issue, researchers have turned to the use of optical waves instead of electronic signals. Optical waves offer significant information-carrying capacity and minimal loss, but the challenge lies in miniaturizing photonic devices as much as electronic components.

Enter plasmonics, a research area that combines microscale photonics and nanoscale electronics to overcome this limitation [1]. Using surface plasmon polaritons (SPPs) to deliver light energy between nanophotonic devices, plasmonics offers a high degree of confinement, overcoming the limitations of conventional dielectric waveguides. With plasmonics, it is possible to manipulate light at the nanoscale and create a world of possibilities for the future of data processing.

However, a significant challenge arises in simultaneously achieving longer propagation lengths and highly confined SPP modes. This is where Floquet engineering comes in. This cutting-edge technology transforms quantum material engineering through high-intensity periodic driving, allowing researchers to manipulate matter in previously considered impossible [2, 3].

To address this challenge, we have proposed a comprehensive theoretical framework that uses quantum electrodynamics coupled with Floquet engineering to enhance the propagation length of SPP modes [4]. By modifying the electrical and optical characteristics of metal nanostructures within plasmonic waveguides, it is possible to enhance SPP propagation lengths significantly.

It was observed that exposing a metallic system to this particular form of light (dressing field) increases the propagation length of SPP (surface plasmon polariton) modes due to an enhancement in the metal's conductivity. This can be explained by the fact that SPPs are created by the collective movements of electrons in the metal, and the metal's energy loss can be attributed to electron scattering. Dressing by the external field modifies the wave functions and, thereby, the rates, which can improve the conductivity and increase the propagation length of SPP modes.

Finally, the plasmonic and conductive properties of popular plasmonic metals, including silver (Ag), gold (Au), copper (Cu), and aluminum (Al), were analyzed under the illumination of a particular form of light using computer simulation based on code specifically written to explore this novel observation. Based on the evaluation, several metals were found be much suited for application due to their controllable conductivity response. This discovery could lead to the development of efficient and advanced nanoscale plasmonic data processing devices, circuits, and components in the near future.

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