Date of Award
Spring 2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Electrical Engineering (ENAS)
First Advisor
Tang, Hongxing
Abstract
The rapid development of quantum information technology has fueled a vast interest in sourcing the optimal platform according to the application needs. Solid state spin system emerges from many popular choices for its favorable optical and microwave properties to achieve complex functionalities in quantum computing, quantum communication and quantum sensing. Interfacing spins with thin film nanophotonic circuits opens up the opportunities to harvest not only the advantages from spins, including long coherence and high quantum-efficiency fluorescence, but also the advantages of the mature fabrication technologies for low loss, high throughput nanophotonic structures. Such an integrated system with spins plays an important role in realizing an effective quantum network. In this thesis, we present our investigations of some hybridized spin systems with nanophotonic structures, focusing on the spin manipulation through an engineered spin-photon coupling. We first demonstrate an experimental realization of the erbium (Er) implanted thin film lithium niobate (LN) nanophotonic structures. Targeting at the Er optical transition at the telecommunication wavelength, we fabricate low loss LN long waveguides (centi-meter long) and the high-Q ring resonator (Q ~ 1 million). The optical properties of Er ions at the cryogenic temperature are characterized, where the spin-photon coupling is revealed through a Purcell enhanced fluorescence rate. Next, to eliminate the surface effect and reduce the doping damage from ion implantation, we investigate a new SmartCut technique to incorporate Er into thin film LN. The Er ions are homogeneously doped inside the thin film, allowing less surface strain and more uniform mode overlap. The optical coherence of Er ions is studied at the milli-Kelvin temperature environment. By comparing with the original bulk wafer, we demonstrate that the optical coherence of Er ions is unaffected by the SmartCut technique, proving its feasibility and robustness in ion incorporation. We construct the optically thick medium from the optically dilute material as an example to showcase the capability of engineering the spin-photon coupling through nanophotonic structures. The observation of multi-echo train is well explained by the area theorem and opens up new possibilities of encoding quantum information in time bin qubits. Besides the spin-optical interface, we further explore the coupling between the spin and the microwave photons through flip-chip bonding of a Er doped yttrium orthosilicate (YSO) crystal on a high-Q (Q > 100 k) niobium nitride (NbN) microwave resonator. The flip-chip bonding technique maintains the flexibility to adjust the relative orientation of the crystal and the resonator in the applied magnetic field, allowing tuning of the microwave-spin coupling rate. We demonstrate a record-high cooperativity of 650 between spins and planar superconducting microwave resonators. This high cooperativity is vital in quantum information processing with spins such as relaxing the experimental criteria for microwave-to-optical transduction scheme. Finally, we present the preliminary results on the spin echo measurement in the bismuth (Bi) doped silicon (Si) platform. By incorporating the NbN microwave resonator as an on-chip amplifier, we demonstrate the signal-to-noise improvement of the spin echo signal. This marks an important step towards the single spin detection sensitivity.
Recommended Citation
Wang, Sihao, "Spin manipulation with optical and microwave photons in integrated platform" (2023). Yale Graduate School of Arts and Sciences Dissertations. 987.
https://elischolar.library.yale.edu/gsas_dissertations/987
