Theodor W. Hänsch is a world-renowned experimental physicist and Nobel Laureate who has shaped the field of precision laser spectroscopy for over five decades. He currently serves as Director Emeritus at the Max Planck Institute for Quantum Optics in Garching, Germany, and as Professor of Experimental Physics at Ludwig-Maximilians-University Munich. Born in Heidelberg in 1941, Hänsch earned his doctorate summa cum laude from the University of Heidelberg in 1969 before embarking on a postdoctoral fellowship that led him to Stanford University. He established himself as a rising star in atomic physics during his tenure at Stanford, where he served as Associate Professor from 1972 to 1975 and Full Professor from 1975 to 1986. His return to Germany in 1986 marked the beginning of his leadership at the Max Planck Institute for Quantum Optics, which he directed until stepping down as Director Emeritus in 2016.
Professor Hänsch is widely known for his seminal contributions to laser spectroscopy, including the development of the first narrowband tunable dye laser and pioneering techniques of Doppler-free laser spectroscopy. His groundbreaking work in the late 1990s on the optical frequency comb technique revolutionized precision measurement, enabling the counting of light wave oscillations with unprecedented accuracy and facilitating the development of optical atomic clocks. This innovation, which earned him the Nobel Prize in Physics in 2005, has become an indispensable tool in laboratories worldwide, allowing for measurements millions of times more precise than previous spectroscopic methods. Hänsch's research on precision spectroscopy of the hydrogen atom has provided critical tests of quantum electrodynamics, while his work with ultracold atoms led to the first observation of a quantum phase transition between a superfluid state and a Mott insulator crystal. His contributions to the field of laser cooling, including the first proposal for laser cooling of atomic gases, have fundamentally shaped modern atomic physics research.
Beyond his technical innovations, Hänsch has been instrumental in establishing the Max Planck Institute for Quantum Optics as a global center of excellence in quantum physics and precision measurement. His leadership has fostered a collaborative environment where researchers push the boundaries of quantum optics, atomic physics, and precision measurement techniques. Now in his emeritus role, Hänsch continues to guide research on quantum physics of ultracold atoms, high-resolution laser spectroscopy of single trapped ions, and antimatter spectroscopy through his active research group. His laboratory has pioneered numerous experimental techniques including the development of atomic lattices bound by light and the integration of quantum laboratories on microfabricated atom chips. His enduring legacy continues to inspire new generations of physicists who build upon his foundational work to explore quantum phenomena with ever-increasing precision and to develop novel applications in timekeeping, fundamental constant measurements, and quantum information processing.
