Caltech Physicist Honored with Watson Medal

Jonas Zmuidzinas (BS '81), the Merle Kingsley Professor of Physics at Caltech, will receive the 2026 James Craig Watson Medal, a National Academy of Sciences honor presented every two years for "outstanding contributions to the science of astronomy." The award comes with a $25,000 prize, $50,000 of research support, and a gold-plated bronze medal.

Zmuidzinas has spent his career building innovative detector technologies and instrumentation for space, airborne, and ground-based observatories, including the Caltech Submillimeter Observatory (formerly atop Maunakea in Hawaiʻi), the Herschel Space Observatory, and NASA's Kuiper Airborne Observatory.

His inventions include superconducting microwave kinetic inductance detectors (MKIDs or KIDs), which would fly aboard NASA's proposed PRIMA (PRobe far-Infrared Mission for Astrophysics), a space mission concept designed to be the most advanced yet for studying far-infrared light emanating from planets, galaxies, and other cosmic objects.

"Jonas is an enormously capable and creative scientist," says Charles Lawrence, former chief scientist for astronomy and physics at NASA's Jet Propulsion Laboratory (JPL) and currently the directorate scientist for the astronomy and physics directorate at JPL, which is managed by Caltech for the agency. "He's good at everything. He has focused his intensive research on building better detectors for science that can only be done at longer wavelengths. His career is extremely impressive."

Zmuidzinas has also held several leadership roles, including as the chief technologist at JPL (2011–16), the inaugural director of JPL's Microdevices Laboratory (2007–11), and director of Caltech Optical Observatories (2018–23).

"I've always been attracted to technical challenges," Zmuidzinas says. "I like to look for ways to overcome a roadblock to progress. Astronomy presents numerous challenges in basic physics: How can we make the measurement? How do we push to the fundamental limits? I'm excited about the discovery potential of new technology and instrumentation."

Zmuidzinas performed the first astronomical demonstration of KIDs at the Caltech Submillimeter Observatory (CSO) in collaboration with Sunil Golwala, professor of physics at Caltech and a former director of CSO. "When I first heard about the KID concept, I immediately thought it was both an incredibly cool idea and the key to major steps forward not just in millimeter, submillimeter, and far-infrared astronomy, but in detecting optical light and potentially dark matter particles," Golwala says. "The broad adoption of KIDs for many current and next-generation instruments attests to Jonas's impact on the field."

For example, KIDs are used in ground-based and balloon-borne observatories such as the IRAM (Institute of Millimetric Radioastronomy) 30-meter telescope in Spain and the NASA-funded Terahertz Intensity Mapper.

Zmuidzinas's work on KIDs is also enabling the proposed PRIMA mission. PRIMA requires superior detectors that can make ultrasensitive observations of faint far-infrared light from deep space. However, reaching the required sensitivity and building arrays of thousands of detectors proved challenging. In 1999, Zmuidzinas and his JPL colleague Rick LeDuc figured out that devices called superconducting microresonators could be used as ultrasensitive detectors and, crucially, could also be made in large arrays using a "frequency-multiplexed" scheme that greatly simplified the wiring and electronics needed for readout of the array.

Today, KID prototype arrays developed at JPL's Microdevices Laboratory under the leadership of JPL's Matt Bradford, demonstrate the detectors' ability to make PRIMA a success. The basic KID concept can also be adapted for photon detection over a very wide range of light wavelengths making up the electromagnetic spectrum. In fact, the first demonstration of the technology in the early 2000s, performed with Zmuidzinas' JPL colleague Peter Day (PhD '93), involved the detection of X-rays.

According to the National Academy of Sciences, the Watson Medial is in recognition of Zmuidzinas' "world-leading development of ultra-sensitive detectors and inventive astronomical instrumentation." The KIDs that he invented are a "transformational technology enabling observations from millimeter to X-ray wavelengths, with applications ranging from cosmology and exoplanet science to neutrino detection and synchrotron X-ray spectroscopy."

More about the Watson medal can be found at the NAS website. Previous Caltech winners include Robert Leighton (BS '41, PhD '47; 1986), Maarten Schmidt (1991), and Roc Cutri (2007).