Optomechanical Spin-Photon Interface in Wide-Bandgap Materials
Date
2023-04-25
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Abstract
The quantum internet—an interconnected network that can distribute and store quantum states—is required to develop the next generation of quantum technologies, such as unconditional secure communication, enhanced metrology, and distributed quantum computing. A key challenge for the distributed quantum network is the lack of an efficient interface between 'stationary' quantum memories and 'flying' photonic qubits at telecommunication wavelengths. Hybrid mechanical systems aim to overcome this challenge by harnessing the ability of mechanical motion to control and couple disparate quantum systems. In recent years, experiments have demonstrated mechanical control of quantum systems suitable for quantum memory, such as defect-based electronic spins in diamond and silicon carbide. However, these demonstrations lack a coherent interface between the mechanical resonator and optics. Cavity optomechanical devices overcome this impediment by integrating mechanical resonators with an optical cavity. Device engineering can maximize cooperativity, which describes the probability of coherent interaction between photon and phonon fields. Furthermore, optomechanical cooperativity can be parametrically enhanced by the intracavity photon number, N. However, large N can increase cavity loss rate if the material platform suffers from nonlinear absorption. As a result, this thesis employs wide-band gap materials, such as diamond and hexagonal boron nitride (hBN), which exhibit negligible nonlinear absorption at telecommunication wavelengths. In this thesis, we demonstrate an emerging platform that realizes an interface between spin quantum memory and telecom photons through their mutual interactions with mechanical motion. The electronic spins of diamond nitrogen-vacancy centers were controlled by mechanical vibrations that were coherently coupled to photons in the telecommunication wavelength band. This approach does not involve the intrinsic optical transitions of a quantum system and is therefore insensitive to spectral diffusion. Furthermore, wavelength scale diamond optical cavities provide access to enhanced infrared local fields, which were utilized to access and investigate a non-fluorescent state of diamond NV center. This result also has implications on the performance of NV-based spin-optomechanical systems. Additionally, a cavity optomechanical system incorporating hBN is demonstrated. hBN is a 2D van der Waals material that holds tremendous potential for quantum optomechanics and spin-optomechanics applications owing to its beneficial mechanical properties.
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Keywords
Nanophotonics, Spin-photon interface, Cavity optomechanics, Diamond NV centers, Hexagonal boron nitride, Spin-photon transduction
Citation
Shandilya, P. K. (2023). Optomechanical spin-photon interface in wide-bandgap materials (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.