Optical Third-Harmonic Generation in Hexagonal Boron Nitride Thin Films
Anna A. Popkova, Ilya M. Antropov, Johannes E. Fröch, Sejeong Kim, Igor Aharonovich, Vladimir O. Bessonov, Alexander S. Solntsev, Andrey A. Fedyanin
Abstract
Hexagonal boron nitride (hBN) is a layered material that exhibits remarkable optical features in the UV, visible, and IR ranges, attractive for applications in modern photonics. Being transparent in a wide spectral range, hBN is now considered an important building block for novel integrated photonic platforms, thus requiring the study of its optical properties. In this work, we report on the measurements of hBN optical cubic nonlinearity χ(3) equal to 8.4 × 10–21 m2/V2 by observing the third-harmonic generation for 1080 nm pump wavelength from mechanically exfoliated hBN flakes with thicknesses varying from 5 to 170 nm. The third-order susceptibility of hBN is close to that of Si3N4 highlighting the potential of hBN for nonlinear applications.