Conférence du vendredi 18 septembre 2026

Non-reciprocal and robust photonics through traveling wave interactions - Gaurav Bahl (University of Illinois Urbana-Champaign)

Abstract Time-reversal symmetry is a defining property for wave excitations (such as photons and phonons) propagating in linear stationary media. While such linearity is advantageous from a design perspective, it leaves us vulnerable to many detrimental effects arising from disorder and defects both at the material level and at the system level. In fact, it is necessary to break time-reversal symmetry to produce important protective devices like isolators and circulators. This talk will describe how traveling wave interactions can be leveraged in photonics for strong symmetry breaking effects. We will discuss how these approaches can help solve scaling challenges for photonic integrated circuits, especially in support of low-temperature quantum technologies and atom-photonic integrated systems. We present experimental demonstrations of record-setting integrated optical isolators without magneto-optics, how magneto-optic Faraday rotation can be emulated, and how the broader class of non-reciprocal behaviors can be used to enable robust devices that are immune to undesirable scattering and defects.

Speaker Biography Dr. Gaurav Bahl is the George B. Grim Professor of Mechanical Science and Engineering at the University of Illinois at Urbana-Champaign and is an Affiliate in the ECE and Physics Departments. He received his PhD and MS degrees in Electrical Engineering from Stanford University in 2010 and 2008, and the BEng degree from McMaster University in 2005. He is a recipient of the Presidential Early Career Award for Scientists and Engineers (PECASE) in 2019, the ONR Director of Research Early Career Grant in 2016, the AFOSR Young Investigator Award in 2015. He was elected as a Fellow of Optica in 2022.