In a groundbreaking development for the field of computing, Hector De Los Santos has made significant strides in plasmon-based logic devices. At the time, De Los Santos was inspired to use plasmons to do computation. This concept came directly out of his first impressions from 2009 after seeing the restrictions that were imposed by conventional CMOS technology. In 2024, he worked with experts from the University of South Carolina, Ohio State University, and Georgia Institute of Technology. Jointly, they achieved successful demonstration of a so-called Y-junction device that represents a really important step forward in plasmon computing.
De Los Santos’ work pushes the boundaries of these established logic device paradigms that are almost exclusively based on current flow. He hopes to be the first to develop a better method that uses wave flows instead. He designed the Y-junction device to be about five square microns. This cutting-edge device has the ability to control one plasmon with another, addressing critical issues such as energy loss and heightened dissipation observed in conventional computing techniques.
The Concept of Plasmon Computing
De Los Santos can be credited with first conceiving plasmon computing, when he observed the trajectory of CMOS logic technology. He understood that fundamental reductions in transistor size could exponentially supercharge performance. He realized that it posed tremendous hurdles such as quantum mechanical effects and bothersome leakage currents.
“I got the idea of plasmon computing around 2009, upon observing the direction in which the field of CMOS logic was going. In particular, they were following the downscaling paradigm… However, if you follow that paradigm to its conclusion… increased power dissipation.” – Hector De Los Santos
The dream of plasmon-based computing lies in fully realizing the potential of plasmons. These plasmons are ripples in electron density, similar to waves on a pond. De Los Santos explains this analogy:
“If you have what is called an electron sea, you can imagine a pond of water. When you disturb the surface, you create waves… You tap this sea of electrons with an electromagnetic wave.” – Hector De Los Santos
Beyond just computational speed, this groundbreaking approach to generative AI holds the potential to greatly decrease energy usage. De Los Santos pointed out that the energy needed to produce a plasmon is extremely low, on the order of attoJoules.
“It takes very, very low energy to create this kind of disturbance… A disturbance propagates faster than a particle.” – Hector De Los Santos
Development of the Y-Junction Device
Considering the performance of state-of-the-art Y-junction devices, de Los Santos and his coworkers indeed built a remarkable device. It proves their functional prototype for plasmonic computing. This device uses a metal layer located on top of an oxide layer. Underneath it all sits a semiconductor wafer, stacked on top of a ground plane below. To initiate the operation, we add a DC voltage directly between this metal and the underlying ground plane. This simple act creates a “static sea of electrons.”
Once created, this electron sea permeates the material, and the incoming electromagnetic wave is free to interact with it and produce plasmons. The device’s configuration allows for an intuitive launching of a bias plasmon. This action takes place only at the very tip of the Y split.
“At the base of the Y, you launch a plasmon… If you don’t do anything, when this plasmon gets to the junction it will split in two.” – Hector De Los Santos
This newfound ability to control the dynamics of the first bias plasmon allows researchers to do this by launching control plasmons at certain angles towards either side of the Y junction. This redirection capability gives the output of either a zero or one, allowing it to act like a binary logic gate.
“You can redirect the original bias plasmon into one leg of the Y.” – Hector De Los Santos
This dual-control logic double-feature mechanism demonstrates the advantages of plasmons in executing logical operations. It could change everything with the way we think about information processing in computing.
Future Challenges and Directions
Despite De Los Santos’ impressive strides in proving plasmonic logic devices, he admits there’s still work to be done on numerous fronts. One major issue being that this new technology is the antithesis of traditional approaches to logic devices. These legacy approaches assume current flows, but the fit really isn’t there.
“I think the main challenge is that the technology doesn’t follow from today’s paradigm… The different concepts that are brought together… are not normally employed by the dominant technology.” – Hector De Los Santos
For widespread adoption and understanding, there is a need for interdisciplinary knowledge encompassing various fields including metal-oxide-semiconductor physics and quantum field theory. De Los Santos stresses the need to democratize this technology and build public support for more basic research to develop it.
Today, De Los Santos is hard at work on plasmonic computing. He’s overall hopeful about the challenges that must still be surmounted, assured that no artificial constraints of creation are holding back advancement. If he’s successful in advancing this field, we will see much bigger innovations in how efficiently we can compute and how much energy we can save.
“I demonstrated the partial device… The next step would be to demonstrate and fabricate the full device… after that gets done, the next step is concatenating them to create a full adder.” – Hector De Los Santos
As he continues his work on plasmonic computing, De Los Santos remains optimistic about overcoming these hurdles, believing that there are no fabrication limitations hindering progress. His dedication to advancing this field could lead to significant innovations in computing efficiency and energy conservation.