➀ John Joannopoulos pioneered photonic crystals and their applications, leading to transformative technologies like optical scalpels and wireless energy transfer;

➁ As director of MIT’s Institute for Soldier Nanotechnologies for nearly 20 years, he fostered interdisciplinary collaborations and innovations in lightweight armor, smart fabrics, and energy systems;

➂ A legendary mentor, he shaped generations of scientists, co-founded six startups (including Omniguide and Witricity), and left a profound legacy in academia and industry.