@article{THESIS,
      recid = {7586},
      author = {Gupta, Shobhit},
      title = {Engineering Long-Lived Rare Earth Dopants for Scalable  Hybrid Quantum Interconnects},
      publisher = {University of Chicago},
      school = {Ph.D.},
      address = {2023-08},
      number = {THESIS},
      pages = {268},
      abstract = {This thesis studies rare-earth ions doped in solid-state  hosts for scalable quantum interconnects. Rare-earth ions  are an ideal candidate for long-distance entanglement  between physically distant and disparate quantum systems  due to their long spin coherence times and narrow optical  linewidths. Among the family of rare-earth elements,  trivalent erbium (Er3+) is particularly interesting due to  its optical emission in the low-loss telecom C-band used in  existing fiber-optic networks. However, prior  demonstrations of erbium qubits are limited to dopants in  bulk host crystals with either degraded optical coherence  or short spin coherence times, which prevent further  advancement of this emerging quantum technology.
We develop  a new rare-earth qubit platform based on epitaxially grown,  single crystal thin films to address these challenges.  Specifically, using cavity-enhanced, spin and optical  spectroscopy, we demonstrate milliseconds spin coherence  times of Er3+ qubits in yttrium oxide (Y2O3) thin films and  gain an understanding of the environment-induced  decoherence
mechanisms with suitable techniques to mitigate  them. We also study the role played by symmetry in  protecting erbium from environmental noise and report kHz  optical dephasing rate of erbium telecom qubits. These  results combined demonstrate a significant prospect of  rare-earth qubits in epitaxial single-crystal films as a  spin-photon interface for quantum
network applications.
},
      url = {http://knowledge.uchicago.edu/record/7586},
      doi = {https://doi.org/10.6082/uchicago.7586},
}