Mikael Rechtsman
Since joining Penn State in 2015, nominators said Rechtsman has made the transition from rising star to international leader in photonics. He earned the Faculty Scholar Medal for Physical Sciences.
Since originating a new subfield of physics as a postdoctoral scholar with Moti Segev at the Technion (Israel Institute of Technology) — namely topological photonics — he has built tremendously on his pioneering work and has pushed into a variety of novel directions, both in topological physics and photonics more broadly, nominators said.
His initial research on this topic, published in Nature in 2013, provided the first experimental demonstration of a topological insulator for light, and the first observation of a “Floquet topological insulator.” These materials represent a new phase of matter with striking properties — they only allow wave propagation on their surfaces, and their properties are left unchanged even in the presence of disorder. They are predicted to have possible applications in photonics, including relating to more efficient lasers and quantum light sources. Nominators called it one of the most active current research areas in photonics and optical physics.
“Rechtsman has pushed into new domains of topological physics, which go significantly beyond what can be realized in condensed matter physics, consistently maintaining his group’s outstanding leadership in topological photonics,” a nominator said. “He has pioneered the exploration of nonlinear topological phenomena, a new area that represents completely different physics than the solid-state world.”
In 2018, in research again published in Nature, Rechtsman offered the first experimental demonstration of four-dimensional quantum Hall physics. Nominators said it was widely believed that quantum Hall physics occurs in four dimensions, yet, until Rechtsman, it had remained unknown since our space is restricted to three dimensions.
“Remarkably, Professor Rechtsman was able to show that in a 2D system, modulation in a two-dimensional parameter space can be used to achieve a topological pump that probes the 4D quantum Hall physics,” a nominator said. “This work significantly opens the way to experimentally explore higher dimensional topological physics.”
Nominators said Rechtsman also made pioneering contributions to the emerging area of nonlinear topological photonics. In papers published in Science in 2020 and Physical Review X in 2021, he reported the experimental observation and explored the properties of solitons — waves that act to guide themselves under conditions of very intense light — in his topological insulator system.
“Prior to his work, most topological photonics work focused on linear systems. Professor Rechtsman’s work again opened a new direction in the field of topological physics,” a nominator said.
He also introduced the concept of broadband topological slow light. This approach overcomes a fundamental trade-off in optical systems, namely between wide bandwidth and slow group velocity. It allows light to propagate unscathed by fabrication defects over long distances and simultaneously with many different wavelengths. As it does this, the light can interact strongly with the matter present, which can make a range of optical processes much more efficient.
“Rechtsman is clearly one of the leaders in the field of photonics,” a nominator said. “Remarkably, he has an entirely new and exciting area of science that is now associated with his name — topological photonics. He demonstrated outstanding scientific achievements and worldwide visibility.”