2022/12/19 by Jakub Lukeš, Lukeš, Jakub, Vít Kanclíř +9
Engineering · Materials Science · Physics and Astronomy · #Applied Physics (physics.app-ph) #Dielectric #FOS: Physical sciences #Ferroelectricity #Laser #Materials science #Nanotechnology #Nonlinear optics #Optics #Optics (physics.optics) #Optoelectronics #Photonic and Optical Devices #Photorefractive and Nonlinear Optics #Poling #Second-harmonic generation #Second-harmonic imaging microscopy #Silicon #Silicon Nanostructures and Photoluminescence #Silicon nitride #Silicon oxynitride #Thin film
paper · pdf · doi:10.48550/arxiv.2212.09411
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2022/12/19 · openalex created_date 2023/01/04 · openalex updated_date 2026/08/05
Strong second harmonic generation (SHG) in silicon nitride has been extensively studied-among others, in terms of laser-induced SHG enhancement in Si3N4 waveguides. This enhancement has been ascribed to the all-optical poling induced by the coherent photogalvanic effect. Yet, an analogous process for Si3N4 thin films has not been reported. Our article reports on the observation of laser-induced 3-fold SHG enhancement in Si3N4 thin films. The observed enhancement has many features similar to all-optical poling, such as highly nonlinear power dependence, cumulative effect, or connection to the Si3N4-Si interface. However, identical experiments for low-oxygen silicon oxynitride thin films lead to complex behavior, including laser-induced SHG reduction. By a thorough experimental study, the observed results were ascribed to heat-induced SHG variation caused by multiphoton absorption. Such behavior indicates that the origin of optically-induced SHG enhancement in SiOxNy-Si structures can be a complex interplay of various phenomena.