DOI: 10.5061/dryad.xgxd254s8
title: Cavity quantum electrodynamics in a high numerical aperture resonator

description: From fundamental studies of light-matter interaction to applications in
 quantum networking and sensing, cavity quantum electrodynamics (QED)
 provides a toolbox to control interactions between atoms and photons. The
 coherence of interactions is determined by the single-pass atomic
 absorption and the number of photon round-trips. Reducing the cavity loss
 has enabled resonators supporting~1-million roundtrips, but with limited
 material choices and increased alignment sensitivity. Here we present a
 high numerical-aperture,lens-based resonator that pushes the
 single-atom-single-photon absorption probability near its fundamental
 limit by reducing the mode size at the atom to order lambda. This
 resonator provides a single-atom cooperativity of 1.6 in a cavity where
 the light circulates only~10times. We load a single 87Rb atom into this
 cavity, observe strong coupling, and demonstrate cavity-enhanced detection
 with fidelity of 99.55(6)% and survival of 99.89(4)% in 130 microseconds.
 Introducing intra-cavity imaging systems will enable cavity arrays
 compatible with Rydberg atom arrays computing technologies, expanding the
 the applicability of the cavity QED toolbox.
description: This data was collected using a single photon counter and
 processed using Jupyter Notebook (python)
description: # Cavity quantum electrodynamics in a high numerical aperture resonator
 [https://doi.org/10.5061/dryad.xgxd254s8](https://doi.org/10.5061/dryad.xgxd254s8) ## Description of the data and file structure Data was taken on the Small Waist apparatus in the Simon Lab at Stanford university.  ### Files and variables #### File: DATA\_afm\_waist\_scan.csv **Description:** 2D heat map of afm cavity waist scan ##### Variables: * x, measured in units of microns. A scan of the afm tip to measure the waist in x * y, measured in units of microns. A scan of the afm tip to measure the waist in y #### File: DATA\_cavity\_spectrum.csv ##### Variables * Mirror Displacement (microns): translating the cavity length allows one to scan through resonances * Transmission (arbitrary units): the amount of light circulating in the cavity varies as we sweep through the resonances #### File: DATA\_fidelity\_counts.csv **Description:** histogram counts, 1 ms bin size ##### Variables * Counts over time, PGC molasses light impinges on the atoms, the fluorescence level is collected by the cavity, the photon counts are measured on an SCPM #### File: DATA\_g2\_dipole\_full.csv ##### Variables * Time (us): the time axis for correlations between events on the spcm. * g2: a measure of the probability of detecting a second photon given that one photon is detected. For thermal states, such a measurement is one. Correlations and anti-correlations can be telling of the underlying physics #### File: DATA\_telegraph\_trace\_fourth.csv ##### Variables * Time (ms): the duration that PGC light is shining on the atoms * Rate (kHz): The rate of collected photons on the single photon counter module #### File: DATA\_g2\_dipole\_inset.csv ##### Variables * Time (us): the time axis for correlations between events on the spcm. * g2: a measure of the probability of detecting a second photon given that one photon is detected. For thermal states, such a measurement is one. Correlations and anti-correlations can be telling of the underlying physics #### File: DATA\_vrs.csv ##### Variables * Light-Cavity Detuning (MHz): The frequency of light driving the cavity can be tuned in order to reveal the response function of the atom-cavity system  * Transmission (arb): For a hybridized, strongly coupled atom-cavity system, the response showcases two peaks split out by the coupling between the atom and the cavity #### File: DATA\_telegraph\_trace\_three.csv ##### Variables * Time (ms): the duration that PGC light is shining on the atoms * Rate (kHz): The rate of collected photons on the single photon counter module #### File: DATA\_telegraph\_trace\_one.csv ##### Variables * Time (ms): the duration that PGC light is shining on the atoms * Rate (kHz): the rate of collected photons on the single photon counter module #### File: DATA\_g2\_lattice\_full.csv ##### Variables * Time (us): the time axis for correlations between events on the spcm. * g2: a measure of the probability of detecting a second photon given that one photon is detected. For thermal states, such a measurement is one. Correlations and anti-correlations can be telling of the underlying physics #### File: DATA\_histogram\_in\_lattice.csv **Description:** histogram counts over time (5 ms) ##### Variables * counts over time: PGC molasses light impinges on the atoms, the fluorescence level is collected by the cavity, the photon counts are measured on an SCPM #### File: DATA\_g2\_lattice\_inset.csv ##### Variables * Time (us): the time axis for correlations between events on the spcm. * g2: a measure of the probability of detecting a second photon given that one photon is detected. For thermal states, such a measurement is one. Correlations and anti-correlations can be telling of the underlying physics #### File: DATA\_early\_time\_dynamics.csv ##### Variables * Time (ms): the duration that PGC light is shining on the atoms * Rate (kHz): the rate of collected photons on the single photon counter module #### File: DATA\_telegraph\_trace\_two.csv ##### Variables * Time (ms): the duration that PGC light is shining on the atoms * Rate (kHz): the rate of collected photons on the single photon counter module #### File: DATA\_histogram\_in\_dipole\_trap.csv **Description:** histogram counts over time (5 ms) ##### Variables * counts over time ## Code/software Python analysis ## Access information Other publicly accessible locations of the data: * None Data was derived from the following sources: * All data was taken in the Simon Lab at Stanford