Optical-Sideband Cooling of Visible Atom Cloud Confined in Parabolic Well

Neuhauser, W.; Hohenstatt, M.; Toschek, P. E.; Dehmelt, Hans

doi:10.1103/physrevlett.41.233

Cited by 528 publications

(237 citation statements)

References 3 publications

Supporting

Mentioning

226

Contrasting

Unclassified

Order By: Relevance

“…Denoting by |n the number states of the mechanical oscillator we have anti-Stokes (Stokes) processes in which the transition |0 p |n → |1 p |n − 1 (|0 p |n → |1 p |n+1 ) followed by the decay of the cavity photon leads to cooling (amplification). This scenario is thus similar to the laser cooling of a trapped ion in the Lamb-Dicke regime [4,5,19], or of a nanomechanical resonator coupled to an "artificial atom" [20] or an ion [21]. An important caveat in this analogy is that there is no external driving for η = 0.…”

mentioning

confidence: 92%

Theory of Ground State Cooling of a Mechanical Oscillator Using Dynamical Backaction

et al. 2007

View full text Add to dashboard Cite

A quantum theory of cooling of a mechanical oscillator by radiation pressure-induced dynamical back-action is developed, which is analogous to sideband cooling of trapped ions. We find that final occupancies well below unity can be attained when the mechanical oscillation frequency is larger than the cavity linewidth. It is shown that the final average occupancy can be retrieved directly from the optical output spectrum.PACS numbers: 42.65. Sf ,42.65.Ky, 42.79.Gn Mesoscopic mechanical oscillators are currently attracting interest due to their potential to enhance the sensitivity of displacement measurements [1] and to probe the quantum to classical transition of a macroscopic degree of freedom [2,3]. A prerequisite for these applications is the capability of initializing an oscillator with a long phonon lifetime in its quantum ground state. So far this has not been demonstrated because the combination of sufficiently high mechanical frequencies (ω m /2π) and quality factors in the relevant regime ω m ≫ k B T has not been reached [3]. In contrast, in atomic physics laser cooling has enabled the preparation of motional ground states [4,5]. This has prompted researchers to study means of cooling a single mechanical resonator mode directly using laser radiation. Early work demonstrated cooling of a mechanical degree of freedom of a Fabry-Pérot mirror using a radiation pressure force controlled by an electronic feedback scheme [6,7], in analogy to stochastic cooling. In contrast, the radiation pressure induced coupling of an optical cavity mode to a mechanical oscillator [cf. Fig. 1(a)] can give rise to self-cooling via dynamical back-action [8]. In essence, the cavity delay induces correlations between the radiation pressure force and the thermal Brownian motion that lead to cooling or amplification, depending on the laser detuning. In a series of recent experiments, these effects have been used to cool a single mechanical mode [9,10,11]. While classical and semiclassical analysis of dynamical back-action have been developed [13,14], the question as to whether ground state cooling is possible has not been addressed.Here a quantum theory of cooling via dynamical backaction is presented. We find that final occupancies below unity can indeed be attained when the optical cavity's lifetime is comparable to or exceeds the mechanical oscillation period. Along these lines, an analogy between this mechanism and the sideband cooling of trapped ions in the Lamb-Dicke regime is elucidated [5]. In our setting the optical cavity mode plays the role of the ion's pseudospin mediating the frequency up-conversion underlying the cooling cycle. Finally, we discuss how the average phonon occupancy can be retrieved from the spectrum of the optical cavity output. We note that these results can be applied to a wide range of experimental realizations of cavity self-cooling [9,11,12].We treat the laser driven optical cavity mode coupled to the mechanical resonator mode as an open quantum system and adopt a rotating frame at the laser freq...

show abstract

mentioning

confidence: 92%

Theory of Ground State Cooling of a Mechanical Oscillator Using Dynamical Backaction

et al. 2007

View full text Add to dashboard Cite

show abstract

“…1. The same spectrum describes the rate at which photons are scattered from state je͘, and one can infer from it the cooling effect of the laser excitation on the ion [21].…”

Section: Ground State Laser Cooling Using Electromagnetically Inducedmentioning

confidence: 99%

Ground State Laser Cooling Using Electromagnetically Induced Transparency

2000

View full text Add to dashboard Cite

A laser cooling method for trapped atoms is described which achieves ground state cooling by exploiting quantum interference in a driven L-shaped arrangement of atomic levels. The scheme is technically simpler than existing methods of sideband cooling, yet it can be significantly more efficient, in particular when several motional modes are involved, and it does not impose restrictions on the transition linewidth. We study the full quantum mechanical model of the cooling process for one motional degree of freedom and show that a rate equation provides a good approximation.

show abstract

“…To investigate the quantitative capability of these fluorescence techniques, the laser-induced fragmentation of trapped Alexa I on traps provide a controlled environment in which fluorescence measurements can be performed on an ensemble of ions over timescales sufficient to consider small ion numbers and slow reaction rates. Laserinduced fluorescence measurements of trapped ions have been used in spectroscopic studies of atomic structure [1][2][3][4], the vibrational spectra of small molecules [5][6][7][8], as well as to characterize the dynamic cooling [9] and crystallization of atomic ions [10 -12].This paper introduces techniques that eliminate the detection of laser background scattering on trap apertures and internal surfaces allowing measurements to achieve both high sensitivity and large dynamic range. In previous pulsed laser measurements of molecular fluorescence collected from trapped species (discussed in references [5][6][7][8]), the radiative lifetimes were sufficiently long to allow collection of fluorescence radiation after the laser pulse.…”

mentioning

confidence: 99%

“…Analysis of photon statistics indicated an average of ϳ10 photons were incident on the PMT detector per 15 ns pulse for ϳ10 3 I on traps provide a controlled environment in which fluorescence measurements can be performed on an ensemble of ions over timescales sufficient to consider small ion numbers and slow reaction rates. Laserinduced fluorescence measurements of trapped ions have been used in spectroscopic studies of atomic structure [1][2][3][4], the vibrational spectra of small molecules [5][6][7][8], as well as to characterize the dynamic cooling [9] and crystallization of atomic ions [10 -12].…”

mentioning

confidence: 99%

Pulsed fluorescence measurements of trapped molecular ions with zero background detection

Khoury¹,

Rodriguez‐Cruz²,

Parks³

2002

J Am Soc Mass Spectrom

View full text Add to dashboard Cite

Sensitive methods have been developed to measure laser-induced fluorescence from trapped ions by reducing the detection of background scattering to zero levels during the laser excitation pulse. The laser beam diameter has been reduced to ϳ150 m to eliminate scattering on trap apertures and the resulting laser-ion interaction is limited to a volume of ϳ10 Ϫ5 cm 3 which is ϳ0.03-0.15 of the total ion cloud volume depending on experimental conditions. The detection optics collected fluorescence only from within the solid angle defined by laser-ion interaction volume. Rhodamine 640 and Alexa Fluor 350 ions, commonly used as fluorescence resonance energy transfer (FRET) fluorophores, were generated in the gas phase by using electrospray ionization and injected into a radiofrequency Paul trap where they were stored and exposed to Nd:YAG laser pulses at 532 and 355 nm for times up to 10 m. Fluorescence emitted by these ions was investigated for several trap q z values and ion cloud temperatures. Analysis of photon statistics indicated an average of ϳ10 photons were incident on the PMT detector per 15 ns pulse for ϳ10 3 trapped ions in the interaction volume. Fluorescence measurements displayed a dependence on trapped ion number which were consistent with calculations of the space charge limited ion density. To investigate the quantitative capability of these fluorescence techniques, the laser-induced fragmentation of trapped Alexa I on traps provide a controlled environment in which fluorescence measurements can be performed on an ensemble of ions over timescales sufficient to consider small ion numbers and slow reaction rates. Laserinduced fluorescence measurements of trapped ions have been used in spectroscopic studies of atomic structure [1][2][3][4], the vibrational spectra of small molecules [5][6][7][8], as well as to characterize the dynamic cooling [9] and crystallization of atomic ions [10 -12].This paper introduces techniques that eliminate the detection of laser background scattering on trap apertures and internal surfaces allowing measurements to achieve both high sensitivity and large dynamic range. In previous pulsed laser measurements of molecular fluorescence collected from trapped species (discussed in references [5][6][7][8]), the radiative lifetimes were sufficiently long to allow collection of fluorescence radiation after the laser pulse. This greatly simplified methods to reduce the detection of background resulting from scattered laser radiation. However, experiments described in this paper apply the Nd:YAG pulsed laser to excite strongly emitting molecules having fluorescence lifetimes shorter than the laser pulse. This required the reduction of background laser scattering during laser excitation, a more demanding constraint.Techniques described in this paper will help to extend fluorescence measurements as an in situ probe of trapped ion properties including chemical identity, the growth and decay of specific ion populations, ion spectroscopy. Fluorescence emission from trapped ions also presen...

show abstract

Optical-Sideband Cooling of Visible Atom Cloud Confined in Parabolic Well

Cited by 528 publications

References 3 publications

Theory of Ground State Cooling of a Mechanical Oscillator Using Dynamical Backaction

Theory of Ground State Cooling of a Mechanical Oscillator Using Dynamical Backaction

Ground State Laser Cooling Using Electromagnetically Induced Transparency

Pulsed fluorescence measurements of trapped molecular ions with zero background detection

Contact Info

Product

Resources

About