title: Magnetically driven second-harmonic generation with phase matching in MnWO₄.
abstract: Phase matching is known to enhance the nonlinear optical response in materials with a non-centrosymmetric crystallographic or electronic structure. In contrast, phase-matched frequency doubling driven by non-centrosymmetric magnetism that induces acentricity in otherwise centrosymmetric structures has not been reported yet. In our study we demonstrate the emergence of magnetically driven second-harmonic generation (SHG) with phase matching in MnWO4. The phase-matched wavelength for SHG can be tuned continuously between 450 nm to 630 nm with the conversion efficiency being determined by the refractive indices and their dispersion. Our findings reveal a new strategy towards magnetism-based conversion-materials and a route for controlling the nonlinear signal yield by acting primarily on the material's spin degree of freedom rather than employing its electronic or structural properties.
authors.forename: Naëmi
authors.initials: N
authors.lastname: Leo
authors.forename: Dennis
authors.initials: D
authors.lastname: Meier
authors.forename: Petra
authors.initials: P
authors.lastname: Becker
authors.forename: Ladislav
authors.initials: L
authors.lastname: Bohatý
authors.forename: Manfred
authors.initials: M
authors.lastname: Fiebig