Quantum Transducer Design and Fabrication

Quantum transducers are devices which translate quantum states in frequency, whether between different optical frequencies or between disparate microwave and optical frequencies.  Microwave-to-optical transducers are the critical technology necessary to optically network superconducting quantum computers to allow the computational power of these microwave systems to scale beyond the confines of a single cryostat.  To preserve quantum states, transducers must operate with high efficiency while adding very little noise.  Thus far, realizing a high bandwidth, quantum-enabled transducer remains an open technical challenge.

This project develops quantum transducers that use a vibrating membrane to mediate between an optical cavity and microwave circuit resonator. Using a doubly parametric approach with strong microwave and optical pumps, efficiencies approaching 50 % have been demonstrated (see references). We are now pursuing quantum-enabled operation (added noise < 1 photon) with mechanically compliant capacitors to achieve electro-mechanical ground state cooling of the membrane. Our design methodology overlays novel superconducting circuitry developed at NIST directly onto the delicate membrane, which requires us to navigate competing fabrication constraints. The device architecture is driven by numerical model optimization of the optical and electrical coupling strengths to the membrane mechanical motion limited by the physical constraints of the hybrid system. We also target modular designs that ease the assembly process, reduce unwanted mechanical vibrations, and increase the number of working devices available for study.

The micro-fabrication of quantum transducers takes place in NIST cleanroom facilities. There, we pattern superconducting circuitry, grow and release silicon nitride membranes with optical quality, and pattern and release drumhead capacitors. In our dedicated optics laboratory, we assemble and align high-finesse optical cavities which surround and excite the micro-fabricated chip assemblies. Our process development emphasizes novel material systems, structural integrity, minimization of surface contaminants, and device yield.

The Quantum Transducer Design and Fabrication Project will:

• Develop novel transducer designs based on vibrating membrane structures
• Model and optimize opto-mechanical and electro-mechanical coupling strengths
• Develop cleanroom fabrication processes with high device yield
• Develop monolithic and modular structures for stability and ease of assembly
• Design and fabricate microwave photonic circuits and test devices

The Results of this Project will Directly Impact:

• Scalable quantum computing
• Secure quantum communications
• Quantum sensing and metrology
• Quantum transducer technology
• Future quantum networking standards
• US leadership in Quantum 2.0 technologies
• US global competitiveness
• US national security 

Literature References

• Entanglement Thresholds of Doubly Parametric Quantum Transducers, Curtis L. Rau, Akira Kyle, Alex Kwiatkowski, Ezad Shojaee, John D. Teufel, Konrad W. Lehnert, and Tasshi Dennis, Phys. Rev. Applied, Vol. 17, 044057, April 2022.
• Optically Distributing Remote Two-Node Microwave Entanglement Using Doubly Parametric Quantum Transducers, Akira Kyle, Curtis L. Rau, William D. Warfield, Alex Kwiatkowski, John D. Teufel, Konrad W. Lehnert, and Tasshi Dennis, Phys. Rev. Applied, Vol. 20, 014055, July 2023.
 

Credit: P. Slayback/NIST

 

Credit: P. Slayback/NIST

Credit: P. Slayback/NIST

 

WANT TO BE INVOLVED?

There are numerous ways to contribute to this project team, which benefits from a diversity of expertise and varied levels of prior experience.

The NRC Postdoctoral Program

The NRC Research Associateship Program has opportunities available for research related to this project (eligibility requirements include US Citizenship). Application cycles are in January and August, and it is recommended that you contact us well in advance of this deadline.

The NIST PREP Program

The NIST Professional Research Experience Program (PREP) was created at NIST-Boulder in 1991 and is designed to provide valuable laboratory experience and financial assistance to undergraduates, graduate students, postdocs, and professional researchers.  The program is intended to assure the continued growth and progress of a highly skilled science, technology, engineering, and math (STEM) workforce in the United States.

The NIST SURF Program

The NIST-Boulder Summer Undergraduate Research Fellowship (SURF) program provides summer research opportunities for undergraduate researchers during an 11-week program.  Students work alongside NIST scientists and will have their own research projects to complete.  Student applications are submitted in February.

Research Collaborations

Collaborations are available to US and international citizens as well as various government agencies. 

If you are interested or have any questions, please contact the group leader, tasshi.dennis [at] nist.gov (Tasshi Dennis).