Lončar, MarkoGhosh, Soumya Shankar2024-06-0120242024-05-102024Ghosh, Soumya Shankar. 2024. Nonlinear Frequency Generation in Periodically Poled Thin Film Lithium Niobate. Doctoral dissertation, Harvard University Graduate School of Arts and Sciences.31296578https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37379033The burgeoning field of nonlinear photonics opens up several exciting possibilities, among them the development of compact, efficient, chip-scale integrated devices for optical frequency manipulation in communication, sensing, and quantum and classical information processing applications. In particular, the thin-film lithium niobate platform stands out for these applications due to its wide transparency window, large second-order optical nonlinearity and electro-optic effect, and fabrication process which is compatible with industry standard techniques. In this work we discuss the design, development, and characterization of several devices for efficient nonlinear frequency generation in thin-film lithium niobate, beginning with visible-to-UV conversion in waveguides towards the goal of realizing precise, integrated ultraviolet light sources for spectroscopy and quantum information applications. We then briefly discuss enhancing second harmonic generation efficiency using periodically poled lithium niobate resonators. Following this is a report of periodically poled lithium niobate waveguides for supercontinuum generation, with intended applications in f − 2f self-referencing for pulsed lasers and frequency combs. We conclude with a brief discussion of the context of these contributions in the current landscape of the field, along with some thoughts on future directions based on this work.application/pdfenOpticsPhysicsApplied physicsThesis or Dissertation2024-06-010009-0009-1459-0885