Coherent Interactions between Brillouin Pathways: Controlled Wideband Excitation of Fano Resonance and Induced Transparency.
ABSTRACT :
Electromagnetically induced transparency (EIT) and Fano resonance are quantum phenomenon which result from the coherent interaction between two excitation pathways. In the case of EIT, this coherent interaction results in the introduction of a transparency window in an otherwise absorption resonance whereas for the Fano resonance this interaction introduces an asymmetry in the Lorentzian profile of a resonance. Recently analogue of EIT and Fano resonance has been demonstrated in a number of systems that range from atomic-plasmonic coupling, opto-mechanical coupling to photonic structures in order to enable applications in the field of sensing, slow-light, switching and microwave photonics. However, controlled excitation of these phenomena over a wide frequency range, which is critical to enable these applications, is challenging. The main challenge with the wide band excitation and control of EIT-like and Fano resonance is the requirement of precise tuning and control of interacting resonances over a large frequency range.
In this talk, i will discuss coherent interaction between the Brillouin Stokes and anti-Stokes resonances in radio frequency domain to demonstrate controlled excitation of Fano resonance and EIT-like resonance over a wide frequency range that extends from 100 MHz to 43 GHz, which is unprecedented. The coherent interaction was achieved using the Brillouin excitation pathways of an off-the-shelf optical fiber, which eliminates the need for precise control over the fabrication and dependence over the state - of - the art nanofabrication facilities. I will talk about optical and electrical control of the Fano and EIT-like resonance and present a model that correctly predicts the profile and other features of these resonances.
ABOUT THE SPEAKER:
Dr. Ravi Pant received his B. Sc. (Hons) and M. Sc. degree in Physics from the University of Delhi in 1995 and 1997 respectively. After finishing his M. Tech. in Optoelectronics and Optical Communications from IIT Delhi in 1998, he worked as a Systems Engineer from 1999 till 2001 before joining PhD at the College of Optical Sciences, University of Arizona. During PhD, his research work was focused on slow-light physics and its applications. After finishing PhD in 2008, he joined Centre for Ultrahigh Bandwidth Devices for Optical Systems (CUDOS), at the University of Sydney (Usyd), as a Postdoctoral Fellow to work on supercontinuum generation. In 2010, Ravi received Australian Research Council (ARC) Postdoctoral Fellowship to work on "Exciting stimulated Brillouin scattering in photonic circuits" where he demonstrated, for the first time, on-chip SBS using travelling wave geometry. In 2013, he joined IISER- TVM as an Assistant Prof in School of Physics, where he is directing the Laboratory for Phoxonics and Nonlinear Optics in Nanostructures" (PHONON) and is a Ramanujan Fellow. His current research is focused on coherent interaction between Brillouin pathways, nonlinear phenomena in micro-resonators and soliton self-frequency shift.