Nonlinear quantum spectroscopy with parity-time-symmetric integrated circuits

Pawan Kumar*, Sina Saravi, Thomas Pertsch, Frank Setzpfandt, Andrey A. Sukhorukov

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review


    We propose a novel quantum nonlinear interferometer design that incorporates a passive parity-time (PT)symmetric coupler sandwiched between two nonlinear sections where signal-idler photon pairs are generated. The PT symmetry enables efficient coupling of the longer-wavelength idler photons and facilitates the sensing of losses in the second waveguide exposed to analyte under investigation, whose absorption can be inferred by measuring only the signal intensity at a shorter wavelength where efficient detectors are readily available. Remarkably, we identify a new phenomenon of sharp signal intensity fringe shift at critical idler loss values, which is distinct from the previously studied PT symmetry breaking. We discuss how such unconventional properties arising from quantum interference can provide a route to enhancing the sensing of analytes and facilitate broadband spectroscopy applications in integrated photonic platforms.

    Original languageEnglish
    Pages (from-to)1763-1776
    Number of pages14
    JournalPhotonics Research
    Issue number7
    Publication statusPublished - Jul 2022


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