Sr atoms (original) (raw)

An optical lattice clock with spin-polarized 87Sr atoms

The European Physical Journal D, 2008

We present a new evaluation of an 87 Sr optical lattice clock using spin polarized atoms. The frequency of the 1 S0 → 3 P0 clock transition is found to be 429 228 004 229 873.6 Hz with a fractional accuracy of 2.6 × 10 −15 , a value that is comparable to the frequency difference between the various primary standards throughout the world. This measurement is in excellent agreement with a previous one of similar accuracy [1]. a e-mail: pierre.lemonde@obspm.fr 1 The first order shift can be made to vanish in this type of clocks at the so-called "magic wavelength".

Accurate Optical Lattice Clock with Sr87 Atoms

Physical Review Letters, 2006

We report a frequency measurement of the 1 S0 − 3 P0 transition of 87 Sr atoms in an optical lattice clock. The frequency is determined to be 429 228 004 229 879 (5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall. Two previous measurements of this transition were found to disagree by about 2 × 10 −13 , i.e. almost four times the combined error bar, instilling doubt on the potential of optical lattice clocks to perform at a high accuracy level. In perfect agreement with one of these two values, our measurement essentially dissipates this doubt. PACS numbers: 06.30.Ft,32.80.-t,42.50.Hz,42.62.Fi 1 S 0 1 P 1 4 6 1 n m / = 3 2 M H z 3 S 1 3 P 0 6 8 9 n m / = 7 , 6 k H z 6 8 8 n m 7 0 7 n m 6 7 9 n m 6 9 8 n m / = 1 m H z 3 P 1 3 P 2 FIG. 1: Relevant energy levels of 87 Sr.

Operating a 87Sr optical lattice clock with high precision and at high density

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2012

We describe recent experimental progress with the JILA Sr optical frequency standard, which has a systematic uncertainty at the 10 −16 fractional frequency level. An upgraded laser system has recently been constructed in our lab which may allow the JILA Sr standard to reach the standard quantum measurement limit and achieve record levels of stability. To take full advantage of these improvements, it will be necessary to operate a lattice clock with a large number of atoms, and systematic frequency shifts resulting from atomic interactions will become increasingly important. We discuss how collisional frequency shifts can arise in an optical lattice clock employing fermionic atoms and describe a novel method by which such systematic effects can be suppressed.

Accuracy Evaluation of a $^{87}\hbox{Sr}$ Optical Lattice Clock

IEEE Transactions on Instrumentation and Measurement, 2000

In this paper, we report the observation of the higher order frequency shift due to the trapping field in a 87 Sr optical lattice clock. We show that at the magic wavelength of the lattice, where the first order term cancels, the higher order shift will not constitute a limitation to the fractional accuracy of the clock at a level of 10 −18 . We also report an accurate frequency measurement of the clock transition. The frequency is determined to be ν1 S 0 − 3 P 0 = 429 228 004 229 879 (5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall.

Systematic Study of the Sr87 Clock Transition in an Optical Lattice

Physical Review Letters, 2006

With ultracold 87 Sr confined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to date of the 1 S 0-3 P 0 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.

Synthetic Spin-Orbit Coupling in an Optical Lattice Clock

Physical review letters, 2016

We propose the use of optical lattice clocks operated with fermionic alkaline-earth atoms to study spin-orbit coupling (SOC) in interacting many-body systems. The SOC emerges naturally during the clock interrogation, when atoms are allowed to tunnel and accumulate a phase set by the ratio of the "magic" lattice wavelength to the clock transition wavelength. We demonstrate how standard protocols such as Rabi and Ramsey spectroscopy that take advantage of the sub-Hertz resolution of state-of-the-art clock lasers can perform momentum-resolved band tomography and determine SOC-induced s-wave collisions in nuclear-spin-polarized fermions. With the use of a second counterpropagating clock beam, we propose a method for engineering controlled atomic transport and study how it is modified by p- and s-wave interactions. The proposed spectroscopic probes provide clean and well-resolved signatures at current clock operating temperatures.

Magic Wavelengths for Optical-Lattice Based Cs and Rb Active Clocks

Atoms, 2020

Active clocks could provide better stabilities during initial stages of measurements over passive clocks, in which stabilities become saturated only after long-term measurements. This unique feature of an active clock has led to search for suitable candidates to construct such clocks. The other challenging task of an atomic clock is to reduce its possible systematics. A major part of the optical lattice atomic clocks based on neutral atoms are reduced by trapping atoms at the magic wavelengths of the optical lattice lasers. Keeping this in mind, we find the magic wavelengths between all possible hyperfine levels of the transitions in Rb and Cs atoms that were earlier considered to be suitable for making optical active clocks. To validate the results, we give the static dipole polarizabilities of Rb and Cs atoms using the electric dipole transition amplitudes that are used to evaluate the dynamic dipole polarizabilities and compare them with the available literature values.

Optical lattice polarization effects on magnetically induced optical atomic clock transitions

Physical Review A, 2007

We derive the frequency shift for a forbidden optical transition J =0→ JЈ = 0 caused by the simultaneous actions of an elliptically polarized lattice field and a static magnetic field. We find that a simple configuration of lattice and magnetic fields leads to a cancellation of this shift to first order in lattice intensity and magnetic field. In this geometry, the second-order lattice intensity shift can be minimized as well by use of optimal lattice polarization. Suppression of these shifts could considerably enhance the performance of the next generation of atomic clocks.

Frequency Shifts in an Optical Lattice Clock Due to Magnetic-Dipole and Electric-Quadrupole Transitions

Physical Review Letters, 2008

We report a hitherto undiscovered frequency shift for forbidden J ¼ 0 ! J ¼ 0 clock transitions excited in atoms confined to an optical lattice. These shifts result from magnetic-dipole and electricquadrupole transitions, which have a spatial dependence in an optical lattice that differs from that of the stronger electric-dipole transitions. In combination with the residual translational motion of atoms in an optical lattice, this spatial mismatch leads to a frequency shift via differential energy level spacing in the lattice wells for ground state and excited state atoms. We estimate that this effect could lead to fractional frequency shifts as large as 10 À16 , which might prevent lattice-based optical clocks from reaching their predicted performance levels. Moreover, these effects could shift the magic wavelength in lattice clocks in three dimensions by as much as 100 MHz, depending on the lattice configuration.

Nondestructive measurement of the transition probability in a Sr optical lattice clock

Physical Review A, 2009

We present the experimental demonstration of non-destructive probing of the 1S0-3P0 clock transition probability in an optical lattice clock with 87Sr atoms. It is based on the phase shift induced by the atoms on a weak off-resonant laser beam. The method we propose is a differential measurement of this phase shift on two modulation sidebands with opposite detuning with respect to the 1S0-1P1 transition, allowing a detection limited by the photon shot noise. We have measured an atomic population of 10^4 atoms with a signal to noise ratio of 100 per cycle, while keeping more than 95% of the atoms in the optical lattice with a depth of 0.1 mK. The method proves simple and robust enough to be operated as part of the whole clock setup. This detection scheme enables us to reuse atoms for subsequent clock state interrogations, dramatically reducing the loading time and thereby improving the clock frequency stability.