Biomedical subjects

Tetsuya Ido

Publications and source records attributed to Tetsuya Ido.

7 recordsLinked to original sources

PubMed2006

Optical atomic coherence at the 1-second time scale.

Highest-resolution laser spectroscopy has generally been limited to single trapped ion systems because of the rapid decoherence that plagues neutral atom ensembles. Precision spectroscopy of ultracold neutral atoms confined in a trapping potential now shows superior optical coherence without any deleterious effects from motional degrees of freedom, revealing optical resonance linewidths at the hertz level with a good signal-to-noise ratio. The resonance quality factor of 2.4 x 10(14) is the highest ever recovered in any form of coherent spectroscopy. The spectral resolution permits direct observation of the breaking of nuclear spin degeneracy for the 1S0 and 3P0 optical clock states of 87Sr under a small magnetic bias field. This optical approach for excitation of nuclear spin states allows an accurate measurement of the differential Landé g factor between 1S0 and 3P0. The optical atomic coherence demonstrated for collective excitation of a large number of atoms will have a strong impact on quantum measurement and precision frequency metrology.

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PubMed2006

Systematic study of the 87Srclock transition in an optical lattice.

With ultracold 87Srconfined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to date of the 1S0-3P0 optical clock transition with a detailed analysis of systematic shifts (19 Hz uncertainty) in the absolute frequency measurement of 429 228 004 229 869 Hz. The high resolution permits an investigation of the optical lattice motional sideband structure. The local oscillator for this optical atomic clock is a stable diode laser with its hertz-level linewidth characterized by an octave-spanning femtosecond frequency comb.

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PubMed2005

High-accuracy optical clock via three-level coherence in neutral bosonic 88Sr.

An optical atomic clock scheme is proposed that utilizes two lasers to establish coherent coupling between the 5s2 1S0 ground state of 88Sr and the first excited state, 5s5p 3P0. The coupling is mediated by the broad 5s5p 1P1 state, exploiting the phenomenon of electromagnetically induced transparency. The effective linewidth of the clock transition can be chosen at will by adjusting the laser intensity. By trapping the 88Sr atoms in an optical lattice, long interaction times with the two lasers are ensured; Doppler and recoil effects are eliminated. Based on a careful analysis of systematic errors, a clock accuracy of better than 2 x 10(-17) is expected.

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PubMed2005

Precision spectroscopy and density-dependent frequency shifts in ultracold Sr.

By varying the density of an ultracold 88Sr sample from 10(9) to>10(12) cm(-3), we make the first definitive measurement of the density-related frequency shift and linewidth broadening of the 1S0-3P1 optical clock transition in an alkaline earth system. In addition, we report the most accurate measurement to date of the 88Sr 1S0-3P1 optical clock transition frequency. Including a detailed analysis of systematic errors, the frequency is [434 829 121 312 334+/-20(stat)+/-33(syst)] Hz.

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PubMed2004

Narrow line cooling: finite photon recoil dynamics.

We present an extensive study of the unique thermal and mechanical dynamics for narrow-line cooling on the 1S0-3P1 88Sr transition. For negative detuning, trap dynamics reveal a transition from the semiclassical regime to the photon-recoil-dominated quantum regime, yielding an absolute minima in the equilibrium temperature below the single-photon-recoil limit. For positive detuning, the cloud divides into discrete momentum packets whose alignment mimics lattice points on a face-centered-cubic crystal. This novel behavior arises from velocity selection and "positive feedback" acceleration due to a finite number of photon recoils. Cooling is also achieved with blue-detuned light around a velocity where gravity balances the radiative force.

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PubMed2003

Recoil-free spectroscopy of neutral Sr atoms in the Lamb-Dicke regime.

Recoil-free as well as Doppler-free spectroscopy was demonstrated on the 1S0-3P1 transition of Sr atoms confined in a one-dimensional optical lattice. By investigating the wavelength and polarization dependence of the ac Stark shift acting on the 1S0 and 3P1(m(J)=0) states, we determined the wavelength where the Stark shifts for both states coincide. This Stark-free optical lattice, allowing the purturbation-free spectroscopy of trapped atoms, may keep neutral-atom based optical standards competitive with single-ion standards.

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PubMed2003

Recoil-limited laser cooling of 87Sr atoms near the Fermi temperature.

A dynamic magneto-optical trap, which relies on the rapid randomization of population in Zeeman substates, has been demonstrated for fermionic strontium atoms on the 1S0-3P1 intercombination transition. The obtained sample, 1x10(6) atoms at a temperature of 2 microK in the trap, was further Doppler cooled and polarized in a far-off resonant optical lattice to achieve 2 times the Fermi temperature.

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