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Alison E. Rugar

Alison Rugar


Engineering Physics


Cornell University


Jeffrey V. Cady

Faculty Sponsor(s): 

Ania C. Bleszynski Jayich

Faculty Sponsor's Department(s): 


Project Title: 

Characterizing Diamond Optomechanical Resonators

Project Description: 

Hybrid quantum systems have recently garnered attention for their potential to combine the strengths and minimize the weaknesses of different quantum systems. Here we investigate hybrid quantum systems consisting of nitrogen-vacancy (NV) centers in diamond optomechanical crystals (OMCs), which host high-quality factor (Q), gigahertz-scale mechanical modes. NV centers are atom-like defects in diamond whose highly coherent spin states can be prepared and read out optically. The spin and orbital states of NV centers can also couple to phonons in an OMC via mechanical strain, thus enabling a hybrid quantum system that may mediate interactions between photons, phonons, and spins. For NV centers in a hybrid qubit-mechanical oscillator device, coherent quantum information exchange is possible if the figure of merit cooperativity, , is greater than 1, where g is the strain coupling rate between the mechanical resonator and the NV center spin or orbital excited states, κ is the NV spin or orbital decoherence rate, and γ is the mechanical rethermalization rate. We have built an optical setup that will measure the reflected power from OMCs as a function of incident wavelength. With our collaborators at Stanford, we detected optical modes in our diamond OMC devices at wavelengths below 1500 nm, out of range of the components of our setup, which operate in the 1530-1560 nm band. Using the finite element method software package COMSOL and the optimization function fminsearch in MATLAB, we developed an improved resonator design that gives a zero-point strain of 6×10-8, an optical Q of 6×105, and optical modes in the desired 1530-1560 nm band. Future integration of this system with a confocal microscope would enable the study of the interactions of mechanical modes in OMCs with NV centers at room temperature, a step towards experimentally realizing a hybrid quantum system.