Quantum plasmonics with dressing EM fields: Advancing the design of nanoscale integrated circuits

Envision a realm where light can be meticulously controlled and manipulated at minuscule scales, unlocking unprecedented potentials for nanotechnology and quantum information technology. Recent breakthroughs in quantum research have propelled us closer to a reality that may be more achievable than previously realized.

In this article, we delve into the domain of surface plasmon polaritons (SPPs) and the vast possibilities they offer in revolutionizing the field of quantum optics.

Surface plasmon polaritons (SPPs)

Picture a serene lake on a sunny day. As you drop a small stone into the water, it sets in motion gentle ripples that traverse the surface. Now, imagine light as akin to those undulating ripples. When light encounters the interface of a metal and a dielectric material, it has the power to generate waves, much like the ripples on the lake. This phenomenon is even more intriguing because these light waves can interact with the metal's microscopic constituents, such as electrons. Remarkably, the light waves and electrons synchronize their oscillations, giving rise to an SPP wave.

This new wave gracefully travels along the metal's surface, reminiscent of the lake's ripples but infused with the essence of light. SPPs possess exceptional traits, as they can navigate through minuscule gaps on the metal surface, akin to maneuvering through a labyrinth. Scientists dedicate their studies to SPPs due to their distinctive properties and capabilities beyond those of ordinary light waves. The capacity to traverse such tiny spaces facilitates the development of nanoscale electronic devices, including data processing units and sensors. These advancements pave the way for cutting-edge quantum technologies, promising a future of immense possibilities.

Schottky junction

Traditional SPPs, which occur at a metal and a dielectric material interface, have already demonstrated remarkable potential in nanophotonics. However, scientists have recently made an intriguing discovery that adds a new dimension to this phenomenon.

When metal and semiconductors combine to create a Schottky junction [Fig. 1], something extraordinary unfolds where a separate space charge region emerges at this junction due to the contrasting charge carrier densities between the metal and the semiconductor [1]. This region alters the interface's properties, leading to transformations in the behavior of SPPs. It's akin to unearthing an entirely novel wave at this exceptional interface.

Quantum description of the Schottky junction based dressed SPPs

Our research team has developed a comprehensive theoretical framework grounded in quantum theory [2] that enables accurate predictions of SPP behavior at the Schottky junction when subjected to an external electromagnetic field [Fig. 2]. We published our findings in Scientific Reports.

Through the application of quantum principles, we have derived an expression for the dielectric function of the "dressed" metal. But what exactly does "dressing" entail in this context? Recent scientific breakthroughs have revealed that an external electromagnetic field possesses the ability to "dress" or modify the properties of metals using Floquet engineering techniques [3,4,5]. It is essential to emphasize that these observations can only be comprehended and explained within the framework of quantum theory.

Now, here comes the truly exciting part: This dressing field provides a potent tool to control and enhance the propagation of SPPs. It alters the metal's susceptibility and permittivity functions, thereby transforming its interaction with light and other electromagnetic waves. By adjusting the intensity, frequency and polarization of this external field, we can finely tune the mobility of electrons within the metal. Our findings have revealed that by doing so, we can extend the distance over which SPPs can travel without dissipating energy. This advancement holds crucial implications for the development of practical nanoscale data processing devices in real-world applications.

What implications does all of this hold for our world? Let your imagination soar as you envision a future where incredibly tiny circuits harness the power of light to fuel our devices. These circuits would exhibit exceptional efficiency and process information at astonishing speeds. This breakthrough in controlling and enhancing light propagation at the nanoscale opens up many possibilities for the future of quantum information technology.

The ability to meticulously control light waves paves the way for the development of advanced quantum photonic circuits and devices surpassing current electronic components' capabilities. Picture smartphones that are faster, smaller and more powerful than ever before, effortlessly handling complex tasks. Envision rapid data processing and sharing systems that revolutionize telecommunications, computing, and health care industries.

With such advancements, the landscape of technology and various sectors would undergo profound transformations. These breakthroughs have the potential to reshape our world, enabling remarkable progress in communication, computation, and health care, to name just a few.

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