Nov 16, 2022

Title: Theory and Applications Exceptional Points in Optics

 

Speaker: Prof. Adi Pick

                The Hebrew University of Jerusalem, Israel

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Abstract:

Exceptional points (EPs) are exotic degeneracies that occur in open systems, when several normal modes coalesce into a single degenerate eigenstate. Systems with EPs can have unique physical properties, such as unidirectional transmission, non-reciprocal mode conversion, and ultrahigh (supralinear) sensitivity. Over the last several years, there has been immense progress in the theoretical understanding and experimental realization of EPs, but the field of EP-based applications is still in its infancy.

In this talk, I will present three novel applications of EPs. I will begin by describing a method for enhancing spontaneous emission from quantum emitters by using special degenerate cavities [1-4]. While the vast majority of work in cavity quantum electrodynamics (CQED) relies on enhanced emission rates near non-degenerate cavities (via the Purcell effect), I will show that degenerate EP resonances can be used to surpass the traditional enhancement by two orders of magnitude. Then, I will present a novel approach for controlling photoionization rates in atoms and molecules by applying external control fields [5]. Due to an EP in the atomic energy levels, small changes in the control fields can lead to dramatic changes in the photoionization spectrum. Finally, I will present a protocol for achieving topological and non-reciprocal mode switching in color centers in diamonds (NV) [6]. Although noise is typically an unwanted effect in quantum-information applications, our protocol harnesses the noise and utilizes the topological property of the EP for robust mode conversion.

 

[1] A Pick, B Zhen, OD Miller, CW Hsu, AW Rodriguez, M Soljacic, and SG Johnson, “General theory of spontaneous emission near exceptional points,” Opt. Express. 25, 12325 (2017)

[2] L Ferrier, P Bouteyre, A Pick, S Cueff, NHMM Dang, C Diederichs, A Belarouci, T Benyattou, J.X Zhao, R Su, J Xing, Q Xiong, and HS Nguyen, Phys. Rev. Lett. 129, 083602 (2022)

[3] Z Lin, A Pick, M Loncar, and AW Rodriguez, Inverse design of third-order Dirac exceptional points in photonic crystals. Phys. Rev. Lett. 117, 107402 (2017)

[4] A Pick, Z Lin, and, AW Rodriguez, “Enhanced nonlinear frequency conversion and Purcell enhancement at exceptional points,” Phys. Rev. B 96, 224303 (2017)
[5] A Pick, PR Kapralova-Zdanska, N Moiseyev, “Ab-initio Theory of Photoionization via Resonances,” JPC, 150, 204111 (2019)

[6] A. Pick, S. Silberstein, N. Moiseyev, N. Bar-Gill, “Topological mode switches in NV centers using exceptional points,” Phys. Rev. Research, 1 (1) 013015 (2019)

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Biography:

Dr Adi Pick is a faculty member at the Applied Physics Department of the Hebrew University of Jerusalem (HUJI). She earned her Ph. D. from Harvard University in 2017. Currently, she is directing research of the Quantum Optics Theory Group at HUJI and has made several contributions to the theoretical understanding of open quantum systems and noise in nanophotonics. Her current research interests are in quantum computation and quantum optimal control. She has contributed 25 manuscripts in peer review journals. Dr. Pick is the recipient of the Alon young faculty award, Koshland and Ali Kaufman postdoctoral research prizes, and the Purcell and Ann Wang Excellence Fellowships for PhD research.