---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '21542'
abstract:
- lang: eng
  text: Nonlinear optics has become the workhorse for countless applications in classical
    and quantum optics, from optical bistability to single photon pair generation.
    However, the intrinsic weakness of optical nonlinearity and reciprocity of nonlinear
    interactions generally places stringent limits on the efficiency of nonlinear
    optical processes and their ability to be tailored for advanced applications in
    multimode systems. Here, motivated by recent advances in using non-Hermitian photonics
    and gain/loss engineering to enable non-reciprocal light transport, we explore
    how the interplay between non-Hermiticity and optical nonlinearity leads to a
    fundamentally new regime of nonlinear frequency conversion. We show how non-Hermitian
    coupling between discrete frequency modes can result in non-reciprocal flow of
    energy in a frequency dimension, closely resembling the non-Hermitian skin effect
    (NHSE). Applying our theory to a multimode nonlinear cavity supporting cascaded
    nonlinear processes, we demonstrate chiral energy flow in a frequency dimension,
    leading to long-range frequency shifts of quasi-continuous wave sources, shaped
    frequency combs robust to defects and disorder, terahertz (THz) generation far
    exceeding the Manley-Rowe limit, and nonlinear multimodal limit cycles for multi-frequency
    pump-probe spectroscopy.
article_number: '7544'
article_processing_charge: No
article_type: original
author:
- first_name: Sahil
  full_name: Pontula, Sahil
  last_name: Pontula
- first_name: Sachin
  full_name: Vaidya, Sachin
  last_name: Vaidya
- first_name: Charles
  full_name: Roques-Carmes, Charles
  id: e2e68fc9-6505-11ef-a541-eb4e72cc3e82
  last_name: Roques-Carmes
- first_name: Shiekh Zia
  full_name: Uddin, Shiekh Zia
  last_name: Uddin
- first_name: Marin
  full_name: Soljačić, Marin
  last_name: Soljačić
- first_name: Yannick
  full_name: Salamin, Yannick
  last_name: Salamin
citation:
  ama: Pontula S, Vaidya S, Roques-Carmes C, Uddin SZ, Soljačić M, Salamin Y. Non-reciprocal
    frequency conversion in a non-Hermitian multimode nonlinear system. <i>Nature
    Communications</i>. 2025;16. doi:<a href="https://doi.org/10.1038/s41467-025-62853-0">10.1038/s41467-025-62853-0</a>
  apa: Pontula, S., Vaidya, S., Roques-Carmes, C., Uddin, S. Z., Soljačić, M., &#38;
    Salamin, Y. (2025). Non-reciprocal frequency conversion in a non-Hermitian multimode
    nonlinear system. <i>Nature Communications</i>. Springer Nature. <a href="https://doi.org/10.1038/s41467-025-62853-0">https://doi.org/10.1038/s41467-025-62853-0</a>
  chicago: Pontula, Sahil, Sachin Vaidya, Charles Roques-Carmes, Shiekh Zia Uddin,
    Marin Soljačić, and Yannick Salamin. “Non-Reciprocal Frequency Conversion in a
    Non-Hermitian Multimode Nonlinear System.” <i>Nature Communications</i>. Springer
    Nature, 2025. <a href="https://doi.org/10.1038/s41467-025-62853-0">https://doi.org/10.1038/s41467-025-62853-0</a>.
  ieee: S. Pontula, S. Vaidya, C. Roques-Carmes, S. Z. Uddin, M. Soljačić, and Y.
    Salamin, “Non-reciprocal frequency conversion in a non-Hermitian multimode nonlinear
    system,” <i>Nature Communications</i>, vol. 16. Springer Nature, 2025.
  ista: Pontula S, Vaidya S, Roques-Carmes C, Uddin SZ, Soljačić M, Salamin Y. 2025.
    Non-reciprocal frequency conversion in a non-Hermitian multimode nonlinear system.
    Nature Communications. 16, 7544.
  mla: Pontula, Sahil, et al. “Non-Reciprocal Frequency Conversion in a Non-Hermitian
    Multimode Nonlinear System.” <i>Nature Communications</i>, vol. 16, 7544, Springer
    Nature, 2025, doi:<a href="https://doi.org/10.1038/s41467-025-62853-0">10.1038/s41467-025-62853-0</a>.
  short: S. Pontula, S. Vaidya, C. Roques-Carmes, S.Z. Uddin, M. Soljačić, Y. Salamin,
    Nature Communications 16 (2025).
date_created: 2026-03-30T12:22:47Z
date_published: 2025-08-14T00:00:00Z
date_updated: 2026-04-27T10:06:42Z
day: '14'
ddc:
- '530'
doi: 10.1038/s41467-025-62853-0
extern: '1'
external_id:
  pmid:
  - '40813767'
fulldoi: https://doi.org/10.1038/s41467-025-62853-0
intvolume: '        16'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://doi.org/10.1038/s41467-025-62853-0
month: '08'
oa: 1
oa_version: Published Version
pmid: 1
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Non-reciprocal frequency conversion in a non-Hermitian multimode nonlinear
  system
tmp:
  image: /images/cc_by_nc_nd.png
  legal_code_url: https://creativecommons.org/licenses/by-nc-nd/4.0/legalcode
  name: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
    (CC BY-NC-ND 4.0)
  short: CC BY-NC-ND (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 16
year: '2025'
...