Tune-out wavelengths for metastable helium

Mitroy, Jim; Tang, Li-Yan

doi:10.1103/physreva.88.052515

Cited by 38 publications

(66 citation statements)

References 44 publications

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“…By comparing accurate atomic structure calculations [6] to highprecision isotope shift measurements, nuclear charge radii relative to the (accurately known [7]) 4 He nucleus can be 1 3 122 Page 2 of 8 the upper-and lower-state polarizability are exactly the same, canceling out the differential ac-Stark shift. In helium a high-precision calculation of the ac-polarizability of the 2 3 S level was recently reported [14], and we ourselves have made more approximate calculations on both the 2 3 S and 2 1 S levels [15]. Both works predict the polarizability of the 2 3 S level to vanish at around 413 nm (a so-called tune-out wavelength) which was later confirmed experimentally [16].…”

Section: Introductionmentioning

confidence: 61%

A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength

2016

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extracted. This method was employed to determine charge radii of the halo nuclei 6 He and 8 He [8] but also to measure the 4 He − 3 He differential nuclear charge radius [9,10]. These measurements are relevant to current investigations into the so-called proton radius puzzle which arose when a similar measurement of the proton radius in µH found a 7σ discrepancy with the 2010 CODATA value [11]. Current efforts investigating the nuclear charge radii of µ 3 He + and µ 4 He + are projected to reach an experimental uncertainty at the sub-attometer (am) level [12]. Determinations of the 4 He − 3 He differential nuclear charge radius with comparable accuracy in electronic systems provide a valuable cross-check for these measurements.Currently, the two most accurate measurements of the 4 He − 3 He differential nuclear charge radius have achieved accuracies of 3 [9] and 11 am 2 [10], roughly an order of magnitude less precise than the projection of the µHe experiment, but disagree by 4σ. The former experiment resolved the 2 3 S → 2 3 P transition to within one thousandth of the 1.6-MHz natural linewidth and is not expected to be improved upon in the near future. The latter experiment was performed on the doubly forbidden 2 3 S → 2 1 S transition whose 8 Hz natural linewidth is not a limiting factor but has a very low excitation rate and thus requires a long interaction time. To achieve this He * atoms were cooled to quantum degeneracy (a BoseEinstein condensate (BEC) of 4 He * , and in a degenerate Fermi gas of 3 He * ) and trapped in an optical dipole trap (ODT). The accuracy of this experiment was limited by experimental effects, mainly the ac-Stark shift induced by the ODT.This problem is also encountered in optical lattice clocks where it is solved by employing so-called magic wavelength traps [13]. In a magic wavelength trap, the wavelength of the trapping laser is chosen such that AbstractHigh-precision spectroscopy on the 2 3 S → 2 1 S transition is possible in ultracold optically trapped helium, but the accuracy is limited by the ac-Stark shift induced by the optical dipole trap. To overcome this problem, we have built a trapping laser system at the predicted magic wavelength of 319.8 nm. Our system is based on frequency conversion using commercially available components and produces over 2 W of power at this wavelength. With this system, we show trapping of ultracold atoms, both thermal (~0.2 μk) and in a Bose-Einstein condensate, with a trap lifetime of several seconds, mainly limited by off-resonant scattering .

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Section: Introductionmentioning

confidence: 61%

A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength

2016

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“…These λ zero measurements test theoretical polarizability spectra α(ω) described in references [22][23][24][25][26][27][28][29][30][31][32][33]. To measure λ zero , we apply an irradiance gradient on the paths of a Mach-Zehnder atom beam interferometer [37][38][39].…”

Section: Motivationmentioning

confidence: 88%

“…Tune-out wavelengths occur at roots in the dynamic polarizability spectrum of an atom, and λ zero measurements can serve as benchmark tests of atomic structure calculations [22][23][24][25][26][27][28][29][30][31][32][33]. Here we use decoherence to calibrate the frequency-axis for light-induced phase shift spectra, as we discuss in more detail in Sections 2-4.…”

Section: Introductionmentioning

confidence: 99%

Decoherence Spectroscopy for Atom Interferometry

Trubko

Cronin

2016

Atoms

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Decoherence due to photon scattering in an atom interferometer was studied as a function of laser frequency near an atomic resonance. The resulting decoherence (contrast-loss) spectra will be used to calibrate measurements of tune-out wavelengths that are made with the same apparatus. To support this goal, a theoretical model of decoherence spectroscopy is presented here along with experimental tests of this model.

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“…Several calculations of tune-out wavelengths [7][8][9][10][11][12][13][14]16] use the sum-over-states approach to calculate the dynamic polarizability α(ω), expressed in terms of reduced dipole matrix elements i D k or oscillator strengths f ik . For K between the D1 and D2 lines,…”

Section: Discussionmentioning

confidence: 99%

“…Light at a tune-out wavelength therefore causes zero energy shift (no ac Stark shift) for atoms in a particular state. Precise λ zero measurements [1][2][3][4][5] serve as a means to study several atomic properties including lifetimes; oscillator strengths; oscillator strength ratios; atomic scalar, vector, and tensor polarizabilities and hyperpolarizabilities; the polarization of atomic core electrons; core-valence electron correlations; and relativistic and QED effects on atomic transition amplitudes [6][7][8][9][10][11][12][13][14][15]. Improved knowledge of λ zero values can also be important for several experiments that use species-specific and state-specific optical dipole potentials created with light near a tune-out wavelength [16][17][18][19][20][21][22][23].…”

mentioning

confidence: 99%

Potassium tune-out-wavelength measurement using atom interferometry and a multipass optical cavity

et al. 2017

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The longest tune-out wavelength for potassium atoms, λ zero = 768.9701(4) nm, was measured using an atom interferometer with a large irradiance gradient supported in a multipass optical cavity. Systematic errors in λ zero measurements that arise from laser light, Doppler shifts, and the Earth's rotation are described. The ratio of oscillator strengths for the potassium D2 and D1 lines inferred from this λ zero measurement is ρ = f D2 /f D1 = 2.0066(11), and the ratio of line strengths is R = S D2 /S D1 = 1.9977(11).

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Tune-out wavelengths for metastable helium

Cited by 38 publications

References 44 publications

A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength

A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength

Decoherence Spectroscopy for Atom Interferometry

Potassium tune-out-wavelength measurement using atom interferometry and a multipass optical cavity

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