Abstract
We present experimental results demonstrating the direct third harmonic generation (THG) in a periodically poled lithium niobate (ppLN) crystal. The method we propose relies on standard ppLN architecture (constant poling period) that is properly chosen to satisfy the quasi-phase matching (QPM) between the fundamental and the third harmonic wave. Neither the second harmonic generation (SHG) nor the sum frequency generation (SFG) optimization or their coupling is mandatory for cascaded THG. Indeed, in our approach, the SHG signal remains weak and only serves as "virtual state" to seed the THG that satisfies the overall QPM-THG condition. Numerical simulations reveal that under QPM-THG condition, SHG intensity has rapid spatial variations and its intensity remains weak along the propagation. The theoretical analysis shows that the adiabatic elimination of the second harmonic virtual state allows for an efficient THG, which is experimentally observed. Using this approximation, we show that the set of non-linear coupled wave equations reduce to an effective THG process.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
