The resonance fluorescence spectrum of a laser-cooled trapped ion is theoretically studied in the Lamb-Dicke limit. Angular averaged spectrum around the elastic peak and the motional sidebands is calculated. The widths of the sidebands are shown to be given by the cooling rate of the ion in the trap. In the limit when the trapping force is strong a possibility of dispersive line shapes is predicted. The spectrum derived is also shown to reproduce in the low-intensity limit the earlier perturbative results.The resonance fluorescence spectrum of a laser-cooled trapped ion is theoretically studied in the Lamb-Dicke limit. Angular averaged spectrum around the elastic peak and the motional sidebands is calculated. The widths of the sidebands are shown to be given by the cooling rate of the ion in the trap. In the limit when the trapping force is strong a possibility of dispersive line shapes is predicted. The spectrum derived is also shown to reproduce in the low-intensity limit the earlier perturbative results.

Physical Review AOct 1, 198618 citations

Fluorescence of optically pumped trapped ions

Michael H. Prior, Randall D. Knight

Optics CommunicationsOct 1, 19806 citations

Heterodyne Measurement of the Fluorescent Radiation of a Single Trapped Ion

J. T. Höffges, H.W. Baldauf, T. Eichler +2 more

Abstract The spectrum of the fluorescent radiation of a single trapped 24 Mg + -ion at low excitation intensity was investigated. The measurement was performed by heterodyning the fluorescent radiation with a sideband of the single mode laser radiation used to excite the ion, resulting in a linewidth of 6 Hz. Under identical experimental conditions, the antibunching in the photon statistics of the fluorescent radiation was also investigated. Heterodyne detection and photon correlation measurement are complementary featuring either the wave or the particle nature of the radiation. The combination of both techniques will allow to measure squeezing in resonance fluorescence.Abstract The spectrum of the fluorescent radiation of a single trapped 24 Mg + -ion at low excitation intensity was investigated. The measurement was performed by heterodyning the fluorescent radiation with a sideband of the single mode laser radiation used to excite the ion, resulting in a linewidth of 6 Hz. Under identical experimental conditions, the antibunching in the photon statistics of the fluorescent radiation was also investigated. Heterodyne detection and photon correlation measurement are complementary featuring either the wave or the particle nature of the radiation. The combination of both techniques will allow to measure squeezing in resonance fluorescence.

European Quantum Electronics Conference (EQEC)Jan 1, 19960 citations

Resonance fluorescence of a single ion

J. T. Höffges, H. W. Baldauf, T. Eichler +2 more

Springer eBooksApr 7, 20085 citations

Resonance Fluorescence of A Single Ion

J. T. Höffges, H.W. Baldauf, T. Eichler +2 more

Advances in quantum chemistryJan 1, 19983 citations

Feedback Cooling and Thermometry of a Single Trapped Ion Using a Knife Edge

Hans Dang, Sebastian Luff, Martin Fischer +2 more

We report on a simple and easy to implement method of feedback cooling trapped ions to temperatures below those achievable using only Doppler cooling. Additionally, the feedback cooling results in significantly shorter cooling times. For selected parameters, we demonstrate cooling to temperatures below $\hbarΓ/2 k_\mathrm{B}$ . The motion of a single ion is monitored in real-time, allowing for the generation of a feedback signal that is applied to an auxiliary trap electrode. Motion detection is implemented by imaging the fluorescence photons emitted by the ion onto a knife edge and detecting the transmitted light, a method used so far to cool trapped nanoparticles. The intensity modulation of the fluorescence resulting from the ion motion is used to generate and apply the feedback signal and also to determine the ion temperature. While the method benefits from a high rate of detected scattered photons, which can be a challenge, and which we address by using a parabolic mirror for collecting the fluorescence, we expect the method to also be applicable when using lenses with moderate numerical apertures.We report on a simple and easy to implement method of feedback cooling trapped ions to temperatures below those achievable using only Doppler cooling. Additionally, the feedback cooling results in significantly shorter cooling times. For selected parameters, we demonstrate cooling to temperatures below $\hbarΓ/2 k_\mathrm{B}$. The motion of a single ion is monitored in real-time, allowing for the generation of a feedback signal that is applied to an auxiliary trap electrode. Motion detection is implemented by imaging the fluorescence photons emitted by the ion onto a knife edge and detecting the transmitted light, a method used so far to cool trapped nanoparticles. The intensity modulation of the fluorescence resulting from the ion motion is used to generate and apply the feedback signal and also to determine the ion temperature. While the method benefits from a high rate of detected scattered photons, which can be a challenge, and which we address by using a parabolic mirror for collecting the fluorescence, we expect the method to also be applicable when using lenses with moderate numerical apertures.

quant-pharXiv:2512.16368Physical Review ADec 19, 20250 citations

\hbarΓ/2 k_\mathrm{B}

. The motion of a single ion is monitored in real-time, allowing for the generation of a feedback signal that is applied to an auxiliary trap electrode. Motion detection is implemented by imaging the fluorescence photons emitted by the ion onto a knife edge and detecting the transmitted light, a method used so far to cool trapped nanoparticles. The intensity modulation of the fluorescence resulting from the ion motion is used to generate and apply the feedback signal and also to determine the ion temperature. While the method benefits from a high rate of detected scattered photons, which can be a challenge, and which we address by using a parabolic mirror for collecting the fluorescence, we expect the method to also be applicable when using lenses with moderate numerical apertures.