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Two-photon-assisted collisions in ultracold gases of polar molecules II: Two-photon optical shielding

Gohar Hovhannesyan1,*, Charbel Karam2, Romain Vexiau1, Leon Karpa3, Maxence Lepers2, Nadia Bouloufa-Maafa1, and Olivier Dulieu1

  • *Contact author: gohar.hovhannesyan@cnrs.fr; ghovhannesyan4@gmail.com
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Phys. Rev. Research 8, 033200 – Published 18 August, 2026

DOI: https://doi.org/10.1103/1gx3-4ql5

Abstract

We theoretically investigate the collisions between ultracold polar molecules in the presence of two lasers ensuring a Raman resonant transition on individual molecules to suppress photon scattering, taking the example of bosonic Na23K39 molecules. By varying laser detunings and intensities, we enable a repulsive long-range interaction potential between molecules. After solving a set of coupled Schrödinger equations with the Hamiltonian written in the basis of laser-dressed states of the molecule pair at infinite distance, we identify quasiresonant conditions under which elastic collisions are favored over inelastic and reactive ones, by a factor of about 2, thus demonstrating a promising pathway for efficient two-photon optical shielding of ultracold molecular collisions. The results are analyzed in terms of scattering length of the colliding laser-dressed molecules, which exhibit prominent resonances assigned to the interaction of the entrance channel with other specific channels, consistent with the existence of a quasibound level of the long-range molecular pair induced by the lasers.

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Phys. Rev. Research 8, 033200– Published 18 August, 2026
  • Received 16 February 2026
  • Accepted 22 June 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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