Justus Ndukaife, associate professor of electrical and computer engineering and Chancellor Faculty Fellow, is leading novel research that has developed all-metal thermal emitters to improve the stability of infrared light sources for applications, like gas sensors, that operate under extreme environmental conditions.
The research, “Engineering Thermal Emission with Enhanced Emissivity and Quality Factor Using Bound States in the Continuum and Electromagnetically Induced Absorption,” was published in Advanced Optical Materials on October 26, 2025. The research is supported by a prestigious Office of Naval Research Young Investigator Program (ONR YIP) award.
Thermal emitters are devices that convert thermal energy into electromagnetic energy – emitting thermal radiation as a result – and are widely used for energy harvesting and various applications in technology and industry. In recent years, scientists have explored ways to control thermal radiation, such as transforming it into light that is both narrowband (emitted over a very specific wavelength range) and directional (emitted in a defined direction).
Traditionally, researchers have relied on dielectric materials, like silicon and germanium, to achieve narrowband thermal emission. But the problem with such materials is that their properties change when heated. In contrast, metal-based thermal emitters are more stable. However, they also have a drawback in that they’re prone to significant energy loss, impeding their performance for applications like high-precision gas sensing.
To address this issue, Ndukaife and his team utilized a concept known as Bound States in the Continuum (BIC) to design all-metal thermal emitters that combine the stability of metals with the narrowband emission feature of dielectrics.
By leveraging the BIC effect, the researchers designed and experimentally demonstrated an all-metal thermal emitter with little energy loss, resulting in a record-high Q-factor of 202. Ndukaife said this is the highest reported Q-factor reading to date for any metal-based thermal emitter. The experiments were performed in collaboration with the research group of Josh Caldwell, professor of mechanical and electrical and computer engineering at Vanderbilt. Guodong Zhu, a fifth-year Ph.D. student in Ndukaife’s lab, is a co-author on the study and performed the experimental measurements under Ndukaife’s guidance.
“We wanted to combine the best of both worlds — the spectral stability of metals and the narrowband emission nature of dielectrics — without the limitations of either,” said Ndukaife, a member of the Vanderbilt Institute of Nanoscale Science and Engineering (VINSE). “This is an exciting step toward creating thermal light sources that are efficient, spectrally narrow, and resilient. Such sources could serve as key building blocks for sensors and communication systems operating in extreme or space environments.”
Earlier this year, Ndukaife was selected as one of the 2025 Optica Ambassadors, a distinguished appointment that recognizes his exceptional contributions to the field of optics and photonics, as well as his commitment to mentoring the next generation of leaders in the academia and industry.
Contact: Lucas Johnson, lucas.l.johnson@vanderbilt.edu