Cooling of atoms using an optical frequency comb

Abstract

We report on laser cooling of neutral rubidium atoms by using a single mode of a frequency comb. Cooling is achieved on a dipole-allowed transition at 780 nm in a one-dimensional retro-reflected beam geometry. Temperatures are measured using standard time-of-flight imaging. We show the dependence of the temperature on the cooling time, intensity and detuning of the frequency comb. The lowest temperature achieved is approximately equal to the Doppler temperature and is limited by the intensity of the comb mode driving the cooling transition. Additionally, we verify the analogy between frequency comb and continuous-wave laser cooling. Our work is a step towards laser cooling of atoms with strong cycling transitions in the vacuum ultraviolet, such as hydrogen, deuterium and antihydrogen, where generation of continuous-wave laser light is limited by current laser technology. Achieving efficient cooling at these wavelengths would significantly improve the precision of optical frequency standards, enable measurements of fundamental constants with unprecedented accuracy, improve tests of charge, parity, and time reversal symmetry, and open the way to achieving quantum degeneracy width new atomic species.

Simultaneous dual-species laser cooling using an optical frequency comb

“…This discrepancy can be attributed to several effects that were not taken into account in the theoretical model, such as stray magnetic fields, finite comb mode linewidth, and in particular the spatial beam profile. These results are in line with the measured and calculated FC force on 87 Rb atoms in our recent work [9]. There is also a discrepancy between the calculated and measured force amplitudes around δ ≈ 0 which will be clarified in the following paragraphs.…”

“…f rep is stabilized to a low-noise synthesizer which is referenced to a rubidium frequency standard. A detailed description of the FC stabilization scheme is presented in our recent paper [9].…”

“…We start the investigation of simultaneous interaction of the FC with cold 85 Rb and 87 Rb atoms by measuring the FC radiation pressure force. The experimental setup and the measurement sequence used are similar to the ones described in our recent work [9]. A single circularly polarized FC beam is sent through an AOM for fast switching, and is then directed to the center of the dual-species MOT.…”

“…[32]; more details on the model can be found in Ref. [9]). For the theoretical results shown in Fig.…”

Advanced dispersion engineering of a III-nitride micro-resonator for a blue frequency comb

“…There has been significant progress on both theoretical and experimental fronts, to the point where we now have fully developed spectro-and spatio-temporal models [6,7] of the nonlinear dynamical Kerr-comb generation process inside a micro-resonator, advanced dispersion engineering approaches [8][9][10][11] for micro-resonator design optimization, as well as fabrication processes for Si 3 N 4 -based structures [12][13][14], allowing the manufacture of near-IR micro-resonators with very high quality factors (Q) in a variety of material platforms (Si, SiO 2 , Si 3 N 4 , SiC, diamond, AlN, Al-GaAs, GaP, MgF 2 ). These advances have enabled the laboratory demonstrations of frequency-bin entangled photon sources and Doppler-cooling of atoms/ions [15,16], among others.…”