Optimal sizes of dielectric microspheres for cavity QED with strong coupling

By J. Buck, H. Jeff Kimble. 2002

226 citations recorded by the source corpus.

The whispering gallery modes (WGMs) of quartz microspheres are investigated for the purpose of strong coupling between single photons and atoms in cavity quantum electrodynamics (cavity QED). Within our current understanding of the loss mechanisms of the WGMs, the saturation photon number n0 and critical atom number N0 cannot be minimized simultaneously, so that an "optimal" sphere size is taken to be the radius for which the geometric mean sqrt(n[sub 0]N[sub 0]), is minimized. While a general treatment is given for the dimensionless parameters used to characterize the atom-cavity system, detailed consideration is given to the D2 transition in atomic cesium at lambda0 = 852 nm using fused-silica microspheres, for which the maximum coupling coefficient ga/(2pi)[approximate]750 MHz occurs for a sphere radius a = 3.63 µm corresponding to the minimum for n0[approximate]6.06×10^–6. By contrast, the minimum for N0[approximate]9.00×10^–6 occurs for a sphere radius of a = 8.12 µm, while the optimal sphere size for which sqrt(n[sub 0]N[sub 0]) is minimized occurs at a = 7.83 µm. On an experimental front, we have fabricated fused-silica microspheres with radii a~10 µm and consistently observed quality factors Q>=0.8×10^7. These results for the WGMs are compared with corresponding parameters achieved in Fabry-Perot cavities to demonstrate the significant potential of microspheres as a tool for cavity QED with strong coupling.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/641fb0fffc6ab8d07f83cb5cc5abf1ba617f0d6e

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In Atomic and Molecular Physics, and Optics

In Electrical and Electronic Engineering

Citations in the corpus

Review of Applications of Whispering-Gallery Mode Resonators in Photonics and Nonlinear Optics (2005, unknown): “A possibility of strong coupling between a photon confined in a WGM and an atom was analyzed in [269–271].”
Optical resonators with whispering-gallery modes-part II: applications (2006, background): “The possibility of strong coupling between a photon confined in a WGM and an atom was analyzed in [153]–[155].”
Exponential Improvement in Photon Storage Fidelities Using Subradiance and “Selective Radiance” in Atomic Arrays (2017, background): “The exponential suppression with ring radius is analogous to the scaling of radiation losses in a conventional whispering gallery resonator [68].”
Hybrid quantum circuits: Superconducting circuits interacting with other quantum systems (2012, background): “In other optical cavity systems, such as the microsphere cavity (dielectric spherically symmetric structure) (Buck and Kimble, 2003; Vernooy et al., 1998), the microtoroidal cavity (dielectric rotationally symmetric structure) (Aoki et al., 2006; Armani et al., 2003; Özdemir et al., 2011), and the…”