Renowned Physicist Professor John Joannopoulos, a leading figure in the field of photonics and director of the Institute for Soldier Nanotechnologies,’ life ends at 78 years of age.
John "JJ" Joannopoulos, a renowned researcher in theoretical condensed-matter physics and an early pioneer in the study of photonic crystals, passed away on Aug. 17 at the age of 78. Born in New York City in 1947 to parents who were both immigrants from Greece, Joannopoulos spent his entire 50-year career at MIT, where he was known for his generous and unwavering mentorship.
Joannopoulos set up a group at MIT to study theoretical condensed-matter physics, focusing on ab initio physics, meaning physics "from first principles." In the early 1990s, he recognized a connection between his first-principles work with electrons and the behavior of photons and applied this approach to predict the fundamental behavior of photons in different classes of materials.
One of Joannopoulos's most significant contributions was the discovery of the "perfect mirror," a structure that, when rolled into a tube, could act as a perfect optical conduit. This structure, when light travels through it, reflects and bounces around within the fiber, with none scattering away. In 1998, Joannopoulos and his group showed that a structure made of multiple refractive layers could reflect light coming from any and all angles, challenging a more-than-century-old assumption about light reflection.
The innovations in photonic crystals by Joannopoulos have led to transformative and life-saving technologies. His research on photonic crystals has enabled various technologies including chip-based optical waveguides that guide light with high precision, wireless energy transfer systems, health-monitoring textiles that use light manipulation, and precision light-based surgical tools (optical scalpels), which utilize controlled light propagation for minimally invasive surgery with high accuracy and safety.
Recent advances in photonic crystal biosensors, building on principles Joannopoulos helped establish, demonstrate extremely high sensitivity by leveraging topological light trapping within photonic crystals, improving detection of biomolecules by orders of magnitude. This reflects the ongoing impact of his foundational work.
In addition to his groundbreaking research, Joannopoulos was a loving husband, father, grandfather, friend, and mentor. He was the Francis Wright Davis Professor of Physics at MIT and director of the MIT Institute for Soldier Nanotechnologies (ISN) from 2006 to 2022, facilitating countless collaborations between MIT faculty, industry partners, and the U.S. Department of Defense.
Joannopoulos was the recipient of MIT's Killian Achievement Award in 2022, in recognition of his lifetime contributions to science and his impact as a mentor to generations of students. He was one of the first to pioneer the field of photonic crystals, studying how materials can be manipulated at the nanoscale to control the behavior of light traveling through.
Joannopoulos's legacy in photonics and condensed matter physics will continue to inspire future researchers, and his contributions to science and society will be remembered for generations to come.
