Optics+Photonics 2022: plenaries focus on nanoscience and engineering

24 Aug 2022

Lisa Poulikakos and Keren Bergman present on metasurfaces for bioimaging, and photonic connectivity for AI computing, respectively.

By Matthew Peach in San Diego

Monday’s opening plenary speaker at Optics + Photonics was Dr. Lisa Poulikakos, an assistant professor at the University of California, San Diego (UCSD). She is leading a new branch of research into the potential of colorimetric metasurfaces to enhance the quantitative characterization of biological tissue microstructures.

Her group’s work has the overall aim of better understanding and treating diseases such as cancer, heart disease and Alzheimer’s disease.

Dr. Poulikalos explained how her group is leveraging particular properties of such metasurfaces to scale down the complex manipulation of light and selectively visualize disease-relevant fiber density and orientation in biological tissues.

She told the audience, “Starting with the example of breast cancer diagnostics, we then expand our view to the rich palette of fiber-affecting diseases where metasurfaces hold great potential as rapid, precise, and low-cost tissue diagnostics with facile clinical implementation.”

On-chip imaging

Metasurfaces are enabling “next generation” on-chip imaging of tissue microstructures and how this approach can be deployed to tackle the common, fiber-affecting diseases that can occur throughout many major organs of the human body:

“Metasurfaces visualize the tissue microstructures, differentiating healthy tissue from fibrotic tissue and thereby promise improved treatments, whether in pathological approaches, drug development or endoscopic procedures,” she noted.

Dr. Poulikakos is also a recipient of the ETH Medal, awarded by ETH Zurich to outstanding doctoral theses; the L’Oréal USA For Women in Science Fellowship; she and was Chair of the 2018 Gordon Research Seminar in Plasmonics and Nanophotonics. More information about her work is available here in a recent interview with SPIE.

Photonic connectivity for energy-efficient AI computing

The second plenary talk in the Nanoscience + Engineering field was presented by Dr. Keren Bergman, who is Charles Batchelor Professor of Electrical Engineering at Columbia University (N.Y.) where she also serves as the Faculty Director of the Columbia Nano Initiative.

High-performance data centers are increasingly bottlenecked by the energy and communications costs of interconnection networks. Dr. Bergman said, “Our recent work has shown how integrated silicon photonics with comb-driven dense wavelength-division multiplexing can scale to realize petabyte/s chip escape bandwidths with sub-picojoule/bit energy consumption.”

“We use this emerging interconnect technology to introduce the concept of embedded photonics for deeply disaggregated architectures. Beyond alleviating the bandwidth-energy bottlenecks, the new architectural approach enables flexible connectivity tailored for specific applications,” she said.

‘The future is wide open’

Dr. Bergman concluded: “Hopefully I have made a good case for the data movement that is going to be critical to future computing scale-up. Power consumption right now is one of the limiting factors on really being able to scale these systems. I have focused on AI and those applications because the growth there is so tremendous. This applies to almost all computing systems [including] much more general-purpose computing systems.

“It’s the power consumption and associated with that is the bandwidth density and the costs associated with that. What photonics can do is really break down barriers and bring high bandwidth, relatively low energy consumption connectivity, system-wise,” she continued.

“Right now, we are living with these very hierarchical types of system that have a tremendous amount of bandwidth, relatively low energy on the chip and in close proximity to that chip – but as soon as I get off that node or interposer, I fall off a cliff in terms of the bandwidth that’s available to me and increased energy consumption.

“Photonics can really flatten out that curve and break down boundaries. Then the question comes up: what if I had that kind of flattened architecture where I can communicate from anywhere to anywhere in the system with the bandwidth that’s possible to me only today on the chip itself?

“We have shown that there is at least potential for really big improvements – not just in performance and acceleration – but really in the energy savings and efficiency at reducing the idle elements that are just sitting there in today’s systems, essentially wasting power.

“The future is just wide open in terms of being able to imagine these imposable, aggregated architecture that can be adapted to the growing needs of these data analytic applications.”

Prof. Bergman leads the Lightwave Research Laboratory encompassing multiple cross-disciplinary programs at the intersection of computing and photonics. Prof. Bergman is the recipient of the 2016 IEEE Photonics Engineering Achievement Award and is a Fellow of Optica and IEEE.