Speaker and Affiliation: Dr. Mohammad-Ali Miri, from the Department of Electrical and Computer Engineering at the University of Texas-Austin

Seminar Title: "Parity-time symmetry and the emerging field of non-Hermitian photonics."

Abstract: 

Interest in non-Hermitian systems has been sparked after the realization that a large class of non-Hermitian Hamiltonians can exhibit entirely real spectra as long as they respect parity-time (PT) symmetry. In most cases, such PT-symmetric Hamiltonians involve complex potentials with symmetric and anti-symmetric distributions of their real/imaginary parts. Even though the practicality of this theory, is still a matter of debate in its original community, recently it has been noted that optics, due to the abundance of non-conservative elements of gain and loss, can provide a fertile ground for observing and fruitfully utilizing parity-time symmetry. 

In this talk, the ramifications of parity-time symmetry in optics will be discussed. PT-symmetric structures by utilizing balanced regions of gain and loss can exhibit peculiar properties which do not have a counterpart in traditional Hermitian systems. This has inspired the broader field of non-Hermitian photonics targeting new devices and structures with novel properties and functionalities by exploiting gain and loss as extra degrees of freedom. In particular, I will discuss selective PT-symmetry-breaking in multimode laser cavities as a new approach to enforce single-mode operation. In addition, I will discuss the possibility of breaking the reciprocity of light in a multimode cavity optomechanical system, highlighting the importance of drives and dissipations.

Bio:

Mohammad-Ali Miri is a Postdoctoral Fellow in the Department of Electrical and Computer Engineering at the University of Texas at Austin. He received his B.Sc. and M.Sc. degrees in Electrical Engineering from Shiraz University and Sharif University of Technology in 2008 and 2010 respectively and a Ph.D. in Optics from CREOL, the College of Optics and Photonics, at the University of Central Florida, where he received the Best Doctoral Dissertation Award in 2015. 

Dr. Miri’s research interests are in the broad areas of optics and photonics, light-matter interaction, and nonlinear wave dynamics with a particular emphasis on the physics of parametric and active/passive non-Hermitian systems and their applications in integrated photonics. He has authored and co-authored more than 100 scientific contributions including over 40 publications in peer-reviewed journals.