Watson Lecture, November 11: Alireza Marandi on Using Light to Address Challenges in Sensing and Computing

On Wednesday, November 11, Caltech assistant professor of electrical engineering and applied physics Alireza Marandi continues the 2020-2021 Earnest C. Watson Lectures season by exploring how light can provide opportunities for capturing and processing information.

Titled "The Power of Nonlinearities: Unlocking Opportunities for Sensing and Computing with Light," Marandi's lecture will describe how he and his research group are exploring scientific frontiers in nonlinear photonics, and how their work could enable a broad range of previously less-explored applications for lasers and light detectors, including the potential for at-home breath-analysis devices.

"Think of breath analysis. There is a correlation between the molecular composition of your exhaled breath and what exists in the blood," explains Marandi. "So, there's a lot of useful information about your health contained in your breath, but it is difficult to analyze because the concentrations are so low."

One straightforward way to find out what molecules are inside a person's breath could be to build a spectrometer, a tool with which researchers look at which frequencies of light are absorbed as the beam passes through matter. However, a perfect spectrometer would add weight and unnecessary complexity, and could be problematic to downsize into a device compact enough for at-home use.

"I don't have to spend a lot of time making a full-fledged spectrometer; I just need to make a device from which I can extract the right information," says Marandi. He is developing a sensor that works in the mid-infrared range that can respond to and distinguish a large number of molecules simultaneously. Such a device could be more accurate than a good spectrometer; it could also be smaller and more efficient, allowing it to be scaled down for consumer use.

Using more commercially available compact and inexpensive lasers also presents a sensing challenge: they work best in the visible or near-infrared parts of the spectrum, where the molecular information is not easily accessible. However, Marandi starts with these tools and uses nonlinear photonics to transform his beam into the mid-infrared range where it is most appropriate for molecular sensing.

To Marandi, his solution is an example of when the perfect is the enemy of the good. "You actually want to think about not having a very clean set of information but being able to get enough bits and pieces," he says.

Marandi received his PhD from Stanford University in 2013. Before joining Caltech, he held positions as a postdoctoral scholar and a research engineer at Stanford, a visiting scientist at the National Institute of Informatics in Japan, and a senior engineer in the Advanced Technology Group of Dolby Laboratories. Marandi is a senior member of The Optical Society (OSA) and the Institute of Electrical and Electronics Engineers (IEEE).

Marandi has been the recipient of a National Science Foundation CAREER Program award, the Air Force Young Investigator Program award, and the Young Scientist Prize of the International Union of Pure and Applied Physics. In 2019 he was named the 2019 KNI–Wheatley Scholar in Nanoscience^* at the Kavli Nanoscience Institute.

This online event is free and open to the public. The lecture begins at 5 p.m. and runs approximately 40 minutes; it will be followed by a live audience Q&A with Marandi.

Advance registration is required as capacity is limited. The lecture can also be viewed (without Q&A) on demand starting at 8 p.m. that same evening on Caltech's YouTube channel.

Questions? Contact the Caltech Ticket Office via email at events@caltech.edu or leave a message at (626) 395-4652. Please allow 48 hours for a response. On November 11 only, the Ticket Office phone line will be staffed remotely from 3–5:15 p.m. to provide technical support to Zoom webinar participants and to answer questions about the event.

Named for the late Caltech professor Earnest C. Watson, who founded the series in 1922, the Watson Lectures present Caltech and JPL researchers describing their work to the public. Many past Watson Lectures are available online at Caltech's YouTube channel. Through a gift from the estate of Richard C. Biedebach, the lecture series is also able to highlight assistant professors' research each season. Marandi is a Biedebach lecturer in the 2020–2021 season.

Visit the Watson Lectures page to see the rest of this year's lineup.

^* The KNI-Wheatley Scholar in Nanoscience was established in 2016 as a result of a generous endowment from Caltech alumni Chuck Wheatley and his wife Judy. This new initiative provides seed funding to one tenure-track faculty member, as early-stage proof-of-concept demonstrations are often difficult to support. As envisioned, this award allows junior faculty in nanoscience the flexibility to pursue novel research ideas.