Dissertation/Thesis Abstract

Nonlinear and Quantum Photonics in Thin-Film Lithium Niobate
by Chen, Jiayang, Ph.D., Stevens Institute of Technology, 2020, 148; 27665963
Abstract (Summary)

Second order optical nonlinearities (χ(2)) are central to a plethora of classical and quantum optics studies and applications. In particular, optical parametric processes such as quantum frequency conversion and parametric down conversion are quintessence for many quantum photonics techniques in computing, communications, and metrology. Over the years, lithium niobate (LN) has been a preferred material of choice for those applications due to its large nonlinear tensor (d33 ~27 pm/V), ultrafast electro-optic responses, and a low-loss optical window across from 0.35 um to 5.2 um. Yet conventional lithium niobate devices take the forms of bulk crystal or weakly confined waveguides, which are challenging for dense integration, as needed for hosting complex functionalities. Furthermore, the weak mode confinement limits the achievable interaction and thus requires high laser power to obtain strong nonlinear effects.

In this thesis, we leverage on thin-film lithium niobate (TFLN) platform and advance nanofabrication technology to address the aforementioned challenges. We first develop three different phase-matching schemes, i.e. birefringence modal phase matching, high order mode phase matching and quasi-phase matching, to achieve enhanced optical nonlinearity in lithium niobate nano-structures. Utilizing those integrated nonlinear photonic devices, we observe the quantum Zeno blockade on chip, various efficient parametric frequency conversions and high purity correlated photon pairs (coincidence to accidental ratio ~600). In addition to that, through the dispersion engineering of nanowaveguides, we explore new mechanism to enhance thermal tunability, up to 1.81 nm/K, of the phase matching curve while maintaining ultra-high, up to 1600%/W/cm2, normalized conversion efficiency.

Furthermore, we demonstrate a doubly resonant, periodic-poled thin-film lithium niobate microcavity with half-million quality factor to realize ultra-efficient enhanced photon nonlinearities. It shows a significantly improved single-photon-nonlinearity (~ 10−6), as well as its advantages in stability, scalability and integration. Lastly, we identify a route toward unitary single-photon-nonlinearity (~ 1) based on our recent progress on Z-cut periodic-poled thin-film lithium niobate microring structure.

Indexing (document details)
Advisor: Huang, Yuping
Commitee: Yu, Ting, Strauf, Stefan, Yang, Eui-Hyeok
School: Stevens Institute of Technology
Department: Schaefer School of Engineering & Science
School Location: United States -- New Jersey
Source: DAI-B 81/7(E), Dissertation Abstracts International
Subjects: Physics, Optics
Keywords: Microring, Nonlinear optics, Periodic-poling, Quantum optics, Single photon nonlinearity, Thin-film lithium niobate
Publication Number: 27665963
ISBN: 9781392809648
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