We conduct careful laboratory spectroscopy of gases relevant to climate and exoplanet science. We use our measurements to determine spectroscopic parameters for these gases and improve models for their absorption spectra. These improved models can be used to increase the accuracy of atmospheric greenhouse gas measurements and to interpret spectra of distant exoplanets measured by world-class observatories such as the James Webb Space Telescope.

Laser heterodyne radiometry is an approach for spectroscopy of thermal light based on the interference of thermal light with light from a continuous-wave laser. We are currently working with collaborators at NIST, CU Boulder, Penn State and Carleton College to develop a laser heterodyne radiometer for precision spectroscopy of sunlight. These measurements can be used to study the magnetic and dynamic processes occurring in the sun (relevant to solar physics and exoplanet detection) or to measure greenhouse gases that absorb sunlight as it passes through Earth’s atmosphere.

Optical frequency combs are a special class of laser that can be used as ‘rulers’ for light. Since they were first demonstrated, these sources have revolutionized optical frequency measurements, timekeeping, and spectroscopy. In our work, we take advantage of the unique benefits of frequency combs (e.g. long-term stability and absolute frequency accuracy) to improve the precision and accuracy of measured absorption spectra.