Hector DeLosSantos, a physicist who was a pioneer in the field, first proposed the idea of computing with plasmons in 2010. Fast forward to 2024, and more than 10 years of research has resulted in a significant breakthrough. He and his collaborators from the University of South Carolina, Ohio State University, and the Georgia Institute of Technology developed a unique device that exemplifies the most important component of plasmon-based logic. This pioneering Y-junction device, which is about the size of five square microns, allows one plasmon to control another, highlighting the remarkable progress on the road to new computational technology.
What started De Los Santos’s career into plasmon computing started when he was conducting research around 2009 and saw the limitations of traditional CMOS logic. He noted that as transistors are made smaller to increase performance, they become more susceptible to quantum mechanical effects. This contributes to greater energy dissipation along their path. As such, he began looking for other ways to do computations that would solve for these issues. His goal was to create a computing device with greater efficiency and reversibility. To do this, he harnessed the extraordinary ability of plasmons – quantum excitations of electron density.
Y-junction device precisely controls one plasmon by steering it with another. It does this through the nonlinear combination of many electromagnetic waves with electron charge densities. It signals a new frontier in logic devices, where current paradigms will no longer be enough. De Los Santos is confident that this novel methodology will continue to change the course of next-generation computing.
The Mechanics of the Y-Junction Device
Upon first glance at the principles of operation, the principles of operation are quite different from that of conventional logic devices. Illustration showing a metal structure on top of an oxide layer. This layer is electrically supported by a semiconducting wafer and with a ground plane. We force an arbitrary direct current (DC) voltage between the metal structural element/ground plane pair. By creating a quiescent ocean of electrons with this action, it’s possible to produce plasmon resonance.
“You apply a DC voltage between the metal of the Y and the ground plane, and that generates your static sea of electrons,” – Hector De Los Santos
De Los Santos elaborates on this interaction, stating, “Now, imagine that at the Y junction you apply another wire at an angle to the incoming wire. Along that new wire, you send another plasmon, called a control plasmon. You can use the control plasmon to redirect the original bias plasmon into one leg of the Y.”
This newfound control over plasmons opens up exciting new possibilities for how logical operations are performed. These approaches will require far less energy than today’s technologies.
Overcoming Challenges in Plasmon Computing
Despite the obvious potential behind plasmon technology, De Los Santos is realistic about the challenges that still lay before them. He argues that traditional methods are “doomed” for two primary reasons: conventional devices do not follow the principles of wave flows and as they shrink, energy dissipation becomes increasingly problematic.
“But in my opinion, the usual approaches are just doomed, for two reasons,” – Hector De Los Santos
Unlike standard logic devices, which lose information during computation, energy’s loss, plasmon computation is reversible by design. This characteristic allows it to conserve energy during switching events.
De Los Santos is quick to underscore that understanding what plasmons can do requires specialized knowledge from a variety of fields. This has implications for fields from metal-oxide-semiconductor physics to quantum field theory. Because of this complexity, it will be difficult to communicate and therefore integrate plasmon-based technologies to a wider audience.
“The knowledge base to understand the device rarely exists in a single head,” – Hector De Los Santos
In reaction to all these hurdles, he wants to bring plasmon computing down to earth and into the classroom. He thinks generating more interest in and being able to get sponsorship for more research will be key to moving this exciting new technology forward.
Future Directions for Plasmon-Based Logic
Creating the Y-junction device was just the start, though there’s still a long way to go toward achieving plasmon computing’s full potential. De Los Santos has already shown a proof-of-concept device, describing an arrangement in which two plasmons are able to interact with each other productively. The next step will be to complete fabrication of a full-scale prototype including the addition of dual controls.
“I demonstrated the partial device, that is just the interaction of two plasmons,” – Hector De Los Santos
Once the device is up and running, De Los Santos intends to link several Y-junctions together. This configuration will produce pure computational structures such as full adders, the very basic building blocks of computation.
Plasmon computing has a bright future, thanks to its ultra-low energy needs and blazing operation speeds. De Los Santos highlights this efficiency by stating, “It takes very, very low energy to create this kind of disturbance… The disturbance that you generate propagates very fast.”
Innovative research is speeding ahead to overcome current obstacles in plasmon-based logic systems. Before long, Hector De Los Santos’s dream might reshape the very nature of computing.