Paper 14092-54
Paper 14092-54
Microwave-Assisted Control of Nonlinear Optical Behaviors in Mn–NiO Nanostructures Across Diverse Laser Excitation Regimes
14 April 2026 • 18:10 - 20:00 CEST | Galerie Erasme (Niveau/Level 0)
Abstract
This work examines the tunable nonlinear optical properties of Mn-doped NiO thin films modified by microwave (MW) irradiation. MW exposure induces structural and optical changes that enable controlled adjustment of second- and third-order nonlinearities. Under femtosecond excitation, films irradiated for 8–10 min show the strongest THG due to optimized defect structures and rapid dipole interactions. Nanosecond excitation yields maximum THG for the 10-min film, while picosecond angle-resolved THG peaks for the 2-min sample, highlighting regime-dependent dipolar and thermal effects. SHG, dominated by surface symmetry breaking and lattice distortions, is significantly enhanced only for 10-min irradiation. Z-scan results confirm pronounced third-order nonlinearities. Overall, MW engineering enables dynamic tuning of nonlinear responses for advanced photonic applications.
Presenter
Manipal Institute of Technology, Manipal Academy of Higher Education (India)
Dr. Poornesh P is an Associate Professor in the Department of Physics at Manipal Institute of Technology, Manipal Academy of Higher Education (MAHE). He holds a Ph.D. from National Institute of Technology Karnataka. His research interests include third-order nonlinear optical properties of polymers and semiconductors, optical power limiting materials for eye and sensor protection, second harmonic generation in organic crystals, and AI-based smart sensors using metal oxide semiconductor materials. He has published over 100 papers in peer-reviewed journals.
Dr. Poornesh has served as Principal Investigator for several funded research projects, including:
•An ongoing ANRF-funded project on printable ultralow gas sensors using reduced graphene/metal oxide composites
•A MAHE-funded project (completed) on low-cost gas sensing devices using tungsten oxide nanostructures
•A VGST-DST Karnataka project on optical limiting in organic materials
•A BRNS-DAE project on nonlinear materials.