CAREER: Understanding and Controlling Nonreciprocal Thermal Radiation Exchange Between Surfaces

About This Grant

Thermal radiation refers to energy exchange by electromagnetic waves between heated surfaces. It is common in a wide variety of thermal, energy, and optical systems. Most research has focused on the scenario where the thermal radiation between surfaces is equal in both directions. However, there are important cases where the heat transfer is unequal between surfaces, which is called nonreciprocal radiation exchange. Nonreciprocal radiation exchange is essential in optimizing operations such as solar energy conversion and building insulation. This project will help overcome significant challenges for designing systems with nonreciprocal radiation exchange. For example, the project will conduct experiments to better understand how wide variations in wave frequency of thermal radiation affect energy exchange. The project will construct a numerical modeling method suited for calculating nonreciprocal radiation exchange. Results will help establish a new direction for heat transfer research and generate a direct impact on advanced thermal and energy technologies with significant economic and environmental impacts. The project will also support educational activities including Everything Thermal - a YouTube channel for students and the public to learn about concepts and research in thermal photonics, and P2 - a paper-cutting and painting art demonstration with light and heat to help K-6 students visualize the beauty of symmetry, heat, and optics. The goal of this project is to understand and control the unique directional heat transfer phenomena associated with nonreciprocal surfaces. The research involves achieving broadband nonreciprocal radiative properties, measuring radiative heat exchange between nonreciprocal surfaces, and exploring the tunability of this radiation exchange. Multilayer magnetized materials will be used to broaden nonreciprocity in the infrared, which will provide a general design rationale to achieve broadband nonreciprocity. A modeling method will be established to directly simulate nonreciprocal radiation exchange between surfaces of various geometries and properties. The directional radiative heat transfer will be experimentally measured in an environment with controlled conduction and convection, unraveling the hidden potential of nonreciprocity for advanced photon flow control. The project will serve as a strong foundation to advance radiative thermal and energy technologies with performance approaching the thermodynamic limit. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.