ECE graduate student Phal's research featured on journal cover for a third time


Laura Schmitt

A skilled artist and photographer, ECE doctoral student Yamuna Phal relishes the opportunity to create striking images representing her research. In June, the Journal of Physical Chemistry C featured her work on its cover, marking the third time one of her papers made the cover of a major peer-reviewed journal.

Yamuna Phal
Yamuna Phal

“It was an honor to have my artwork selected for the cover of another journal – it’s  a great source of joy and pride for me,” said Phal, a member of Bioengineering Professor Rohit Bhargava’s Chemical Imaging and Structures Lab. “I enjoy being able to use my artistic side to visually summarize theoretical and complex concepts.”

Phal’s paper, “Resolution limit in infrared chemical imaging,” with former ECE Professor P. Scott Carney, ECE alumnus Luke Pfister, and Bhargava, reports an information theory-based approach to quantify the resolution limit of chemical imaging systems by accounting for signal-to-noise ratio and the multiple wavelengths involved in this type of infrared imaging.

Her work provides an analytical formulation while demonstrating an improved resolution limit for spectral imaging systems compared to conventional optical imaging systems.

Chemical imaging techniques enable both molecular and optical evaluation of a sample, such as a tissue or a polymer, which provides more information about the sample than could be obtained by an optical microscope or spectroscopic measurements alone.

Chemical imaging is an emerging technique with broad applications in biomedical analyses and quality assurance and control for use in the pharmaceutical, polymer, semiconductor, agriculture, and security industries.  Illinois has been a leader in the development of infrared imaging technology and provided both theory and experimental methods that have pushed its limits.

For her cover artwork, Phal depicted the infrared light waves used in chemical imaging as orange spirals illuminating two representative samples. She also created close-up simulations of how conventional imaging techniques and novel chemical imaging methods would perceive the two samples.

“The multiple wavelengths in IR chemical imaging systems enable better spectral contrast,” Phal said. “Thus, the ability to distinguish between samples or the perceived resolution limit, is improved.”

“Chemical imaging is an exciting area, with deep connections to work done at Illinois and in the Electrical and Computer Engineering Department for years,” said Bhargava, a Founder Professor in Bioengineering. “Yamuna and colleagues are helping accelerate our contributions and impact with these studies across many fields, as recognized by cover selections by three journals in just over a year. These selections also recognize the beautiful intersection of art and science.”

Phal’s previous research was featured on the covers of two other journals in 2021. She worked with Dr. Kevin Yeh and Bhargava to report a new chemical imaging technique to measure polarized light-matter interactions. The paper, “Concurrent vibrational circular dichroism measurements with infrared spectroscopic imaging,” made the cover of Analytical Chemistry. This work demonstrated a novel technique of chirality mapping that advanced the capability of current vibrational circular dichroism spectroscopy instruments to enable imaging.

In September 2021, the same team of Phal, Yeh and Bhargava reported another study, “Design considerations for discrete frequency infrared microscopy systems,” which was featured on the cover of Applied Spectroscopy. This paper reviewed the design of instrument configurations for laser-based chemical imaging systems.