In a new study, a physics team at the University of Iowa designed a special microscope that can precisely study the interaction between light and matter that underpins electronic devices, such as those used in interior home lighting, smartphones, televisions and solar panels.

The infrared cryo-microscope, designed by a team led by Thomas Folland, assistant professor in the Department of Physics and Astronomy, uses off-the shelf components to make precise measurements of different materials’ properties. These properties include polaritons, which are quasi‐particles that arise from strong coupling between light and matter. The field of infrared microscopy uses different colors of light and temperature ranges to perform chemical analyses of very small structures and is seen as having the potential to advance electronic technologies.

The microscope allowed the researchers to investigate the temperature properties of a relatively new material, boron nitride. The method the researchers developed and described in the study “allowed us to understand how the optical properties of this material changes with temperature,” Folland says. “This allows us to understand what happens when light travels through the material.” 

“We plan to use the information we gathered as part of a U.S. National Science Foundation-funded program to develop more efficient detectors for heat, where the boron nitride improves the efficiency of the detector,” adds Folland, who leads the Quantum Nanophotonic Materials lab.

The microscope’s design was described in a new study, “Determining the optical and polaritonic properties of isotopically pure hBN using cryogenic FTIR micro-spectroscopy,” published online Jan. 9 in the journal Applied Physics Letters.

Folland is the study’s corresponding author. Three UI undergraduates — Siddharth Nandanwar (now at Boston College), Aditya Desai, and Tristan McMillan — led the preparation of samples, data analysis techniques, and design of the microscope the team used for the measurements. Nandanwar is the paper’s first author, while Desai and McMillan are study co-authors. 

Other study co-authors are S. Maryam Vaghefi Esfidani, from Iowa; and Eli Janzen and James Edgar, from Kansas State University.

The U.S. National Science Foundation, the U.S. Office of Naval Research, and the University of Iowa Office of Undergraduate Research funded the work.