Giant Nonreciprocity and Gyration through Modulation-Induced Hatano-Nelson Coupling in Integrated Photonics

Journal Article · Tue Apr 15 04:00:00 EDT 2025 · Physical Review Letters

DOI:https://doi.org/10.1103/physrevlett.134.153801· OSTI ID:2565135

Örsel, Oğulcan E. ^[1]; Noh, Jiho ^[2]; Zhu, Penghao ^[3]; Yim, Jieun ^[1]; Hughes, Taylor L. ^[1]; Thomale, Ronny ^[4]; Bahl, Gaurav ^[1]

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1. University of Illinois at Urbana-Champaign, IL (United States)
2. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); University of Illinois at Urbana-Champaign, IL (United States)
3. The Ohio State University, Columbus, OH (United States); University of Illinois at Urbana-Champaign, IL (United States)
4. University of Wurzburg (Germany)

Asymmetric energy exchange interactions, also known as Hatano-Nelson type couplings, enable the study of non-Hermitian physics and associated phenomena like the non-Hermitian skin effect and exceptional points (EPs). Since these interactions are by definition nonreciprocal, there have been very few options for implementations in integrated photonics. Here, in this work, we show that asymmetric couplings are readily achievable in integrated photonic systems through time-domain dynamic modulation. We experimentally study this concept using a two-resonator photonic molecule produced in a lithium niobate on insulator platform that is electro-optically modulated by rf stimuli. We demonstrate the dynamic tuning of the Hatano-Nelson coupling between the resonators, surpassing the asymmetry that has been achieved in previous work, to reach an EP for the first time. We are additionally able to flip the relative sign of the couplings for opposite directions by going past the EP. Using this capability, we show that the through-chain transport can be configured to exhibit both giant (~60 dB) optical contrast as well as photonic gyration or nonreciprocal π phase contrast.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); US Army Research Laboratory (USARL); US Department of the Navy, Office of Naval Research (ONR); Defense Advanced Research Projects Agency (DARPA); National Science Foundation (NSF)
• Grant/Contract Number: NA0003525
• OSTI ID: 2565135
• Alternate ID(s): OSTI ID: 2556909
• Report Number(s): SAND--2025-05449J
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 15 Vol. 134; ISSN 0031-9007
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

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