Year: 2026
Type: article
Abstract: Two-dimensional (2D) semiconductors endowed with valley degree of freedom offer potential applications in next-generation petahertz valleytronics and photonics for emerging quantum technologies. We experimentally and theoretically uncover striking signatures of nonperturbative nonlinear optical response in valley-selective photodoped monolayer molybdenum disulfide, highlighting the interplay between strong-field dynamics and valley polarization. The interplay of valley-assisted excitation and circularly polarized probe leads to chiral-sensitive sum and difference frequency mixing of the pump and probe photons, appearing as sidebands in the high-harmonic spectra. Interestingly, the sideband's strength depends on the photodoped valley's chirality and the weaker pump's helicity. Additionally, a circular dichroic signal results from valley-selective photodoping when the pumps's helicity is changed. Sensitivity of the sideband's strength on the pump–probe delay bears an imprint of the temporal aspect of the electron–hole coherence in 2D semiconductors.
Source: Applied Physics Letters
DOI: 10.1063/5.0308260
Institutions: Indian Institute of Technology Bombay, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Université Paris-Saclay, CEA Paris-Saclay, CY Cergy Paris Université, Laboratoire Interactions, Dynamiques et Lasers, Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7124240590