{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/132710"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/132710","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Quantum acoustics with a released thickness-mode mechanical resonator","abstract":"The circuit quantum acoustodynamics (cQAD) platform integrates the strong nonlinearity of superconducting Josephson elements with high-quality mechanical resonators, enabling potential applications in quantum memories, transducers, and sensors. A central challenge in this field is achieving strong electromechanical coupling between the mechanical resonator and the superconducting qubit, while preserving the resonator’s high quality factor. Strong coupling generally favors small mode volumes and often involves metallic components that introduce additional dissipation channels and fabrication complexity. Conversely, larger mode volumes reduce the coupling strength because only the portion of the resonator proximate to the qubit couples effectively. In this work, we address this trade-off by developing a released thickness-mode mechanical resonator based on an aluminum nitride (AlN)-on-silicon (Si) platform. The device is designed to achieve strong piezoelectric coupling to a superconducting qubit. The resonator, with a lateral dimension of approximately $200\\times200$ $\\mu m^2$, is fully released from the Si substrate to minimize clamping losses. Theoretical analysis predicts coupling strengths exceeding 10 MHz between the qubit’s electric field and the resonator’s intrinsic piezoelectric mode. The design, coupling mechanism, and fabrication process of the released AlN thickness-mode resonator are presented in detail. This approach simplifies fabrication, and provides a scalable path toward hybrid quantum systems with high coherence and large electromechanical coupling strengths.","abstract_html":"The circuit quantum acoustodynamics (cQAD) platform integrates the strong nonlinearity of superconducting Josephson elements with high-quality mechanical resonators, enabling potential applications in quantum memories, transducers, and sensors. A central challenge in this field is achieving strong electromechanical coupling between the mechanical resonator and the superconducting qubit, while preserving the resonator’s high quality factor. Strong coupling generally favors small mode volumes and often involves metallic components that introduce additional dissipation channels and fabrication complexity. Conversely, larger mode volumes reduce the coupling strength because only the portion of the resonator proximate to the qubit couples effectively. In this work, we address this trade-off by developing a released thickness-mode mechanical resonator based on an aluminum nitride (AlN)-on-silicon (Si) platform. The device is designed to achieve strong piezoelectric coupling to a superconducting qubit. The resonator, with a lateral dimension of approximately $200\\times200$ <span class=\"etd-inline-math\">&mu; m<sup>2</sup></span>, is fully released from the Si substrate to minimize clamping losses. Theoretical analysis predicts coupling strengths exceeding 10 MHz between the qubit’s electric field and the resonator’s intrinsic piezoelectric mode. The design, coupling mechanism, and fabrication process of the released AlN thickness-mode resonator are presented in detail. This approach simplifies fabrication, and provides a scalable path toward hybrid quantum systems with high coherence and large electromechanical coupling strengths.","abstract_has_math":true,"creators":["Bathala, Sharan Mourya"],"institution":"University of Illinois Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Fang, Kejie"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-12","date_published":"2025-12","updated_at":"2026-07-22T22:25:07Z","subjects":["Quantum Acoustics","Quantum Optomechanics"],"languages":["en"],"rights":["Copyright 2025 Sharan Mourya Bathala"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/132710","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Fang, Kejie"]},{"key":"dc:creator","label":"Author","values":["Bathala, Sharan Mourya"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-12","2025-12-11"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Quantum Acoustics","Quantum Optomechanics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Sharan Mourya Bathala"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/132710"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The circuit quantum acoustodynamics (cQAD) platform integrates the strong nonlinearity of superconducting Josephson elements with high-quality mechanical resonators, enabling potential applications in quantum memories, transducers, and sensors. A central challenge in this field is achieving strong electromechanical coupling between the mechanical resonator and the superconducting qubit, while preserving the resonator’s high quality factor. Strong coupling generally favors small mode volumes and often involves metallic components that introduce additional dissipation channels and fabrication complexity. Conversely, larger mode volumes reduce the coupling strength because only the portion of the resonator proximate to the qubit couples effectively. In this work, we address this trade-off by developing a released thickness-mode mechanical resonator based on an aluminum nitride (AlN)-on-silicon (Si) platform. The device is designed to achieve strong piezoelectric coupling to a superconducting qubit. The resonator, with a lateral dimension of approximately $200\\times200$ $\\mu m^2$, is fully released from the Si substrate to minimize clamping losses. Theoretical analysis predicts coupling strengths exceeding 10 MHz between the qubit’s electric field and the resonator’s intrinsic piezoelectric mode. The design, coupling mechanism, and fabrication process of the released AlN thickness-mode resonator are presented in detail. This approach simplifies fabrication, and provides a scalable path toward hybrid quantum systems with high coherence and large electromechanical coupling strengths.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-12-01","The student, Sharan Mourya Bathala, accepted the attached license on 2025-12-11 at 16:01.","The student, Sharan Mourya Bathala, submitted this Thesis for approval on 2025-12-11 at 16:09.","This Thesis was approved for publication on 2025-12-11 at 16:39.","DSpace SAF Submission Ingestion Package generated from Vireo submission #23137 on 2026-02-19 at 18:46:56"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Quantum acoustics with a released thickness-mode mechanical resonator"]}]}],"canonical_facts":{"dc:contributor":["Fang, Kejie"],"dc:creator":["Bathala, Sharan Mourya"],"dc:date":["2025-12","2025-12-11"],"dc:description":["The circuit quantum acoustodynamics (cQAD) platform integrates the strong nonlinearity of superconducting Josephson elements with high-quality mechanical resonators, enabling potential applications in quantum memories, transducers, and sensors. A central challenge in this field is achieving strong electromechanical coupling between the mechanical resonator and the superconducting qubit, while preserving the resonator’s high quality factor. Strong coupling generally favors small mode volumes and often involves metallic components that introduce additional dissipation channels and fabrication complexity. Conversely, larger mode volumes reduce the coupling strength because only the portion of the resonator proximate to the qubit couples effectively. In this work, we address this trade-off by developing a released thickness-mode mechanical resonator based on an aluminum nitride (AlN)-on-silicon (Si) platform. The device is designed to achieve strong piezoelectric coupling to a superconducting qubit. The resonator, with a lateral dimension of approximately $200\\times200$ $\\mu m^2$, is fully released from the Si substrate to minimize clamping losses. Theoretical analysis predicts coupling strengths exceeding 10 MHz between the qubit’s electric field and the resonator’s intrinsic piezoelectric mode. The design, coupling mechanism, and fabrication process of the released AlN thickness-mode resonator are presented in detail. This approach simplifies fabrication, and provides a scalable path toward hybrid quantum systems with high coherence and large electromechanical coupling strengths.","Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-12-01","The student, Sharan Mourya Bathala, accepted the attached license on 2025-12-11 at 16:01.","The student, Sharan Mourya Bathala, submitted this Thesis for approval on 2025-12-11 at 16:09.","This Thesis was approved for publication on 2025-12-11 at 16:39.","DSpace SAF Submission Ingestion Package generated from Vireo submission #23137 on 2026-02-19 at 18:46:56"],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/132710"],"dc:language":["en"],"dc:rights":["Copyright 2025 Sharan Mourya Bathala"],"dc:subject":["Quantum Acoustics","Quantum Optomechanics"],"dc:title":["Quantum acoustics with a released thickness-mode mechanical resonator"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Electrical & Computer Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:07Z"}