Cavity Optomechanics in Microwave

and Optical Frequencies 

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Jinwoong Cha

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Quantum Technology Institute, Korea Research Institute of Standards and Science

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Nanoscale mechanical vibrations can interact with electromagnetic fields across various frequencies utilizing electromechanical and optomechanical couplings. My talk will discuss some of our on-going work on cavity optomechanics in both microwave and optical regimes, utilizing two distinct platforms. 

I will first describe cavity optomechanics in a niobium-based superconducting microwave device. We employ niobium as a base superconducting material due to its superior superconducting properties, which make it suitable for quantum transduction. Our device demonstrates fundamental optomechanical back-action effects, including motional cooling and amplification, and optomechanically induced transparency at 4.2 K and under strong magnetic fields up to 0.8 T [1]. We further explore optomechanical effects beyond the linear regime with a strong microwave drive, achieving the generation of microwave frequency combs via nonlinear wave-mixing processes [2].

 

Next, I will also discuss our recent efforts on cavity optomechanics using silicon photonic crystal cavities. We realized their cryogenic operations even at millikelvin temperatures and the system exhibits optomechanical interaction with cooperativity C > 1. I will then briefly discuss how these systems can be utilized for microwave-to-optical quantum transduction to realize optical quantum entanglement between two remote superconducting qubits in cryogenic environments.

[1] Nano Letters 21, 1800-1806 (2021).
[2] Nano Letters 22, 5459-5465 (2022).