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All Optical Atomic Clocks Based on a Single Mercury Ion and Calcium Atoms | NIST

Scott A. Diddams, Kurt R. Vogel, Christopher W. Oates +6 more

Jan 1, 20010 citations

Shifts of optical frequency references based on spectral hole burning in Eu3+:Y2SiO5 | NIST

David R. Leibrandt, Michael J. Thorpe, Till Rosenband

Physical Review BMar 6, 20130 citations

OPTICAL FREQUENCY STANDARDS BASED ON COLD CALCIUM ATOMS

Reinaldo L. Cavasso-Filho, Daniela A. Manoel, D. Ortega +3 more

Symposium on Frequency Standards and MetrologyMay 1, 20022 citations

Ramsey-Borde Matter-Wave Interferometry with a Thermal Calcium Beam for Optical Frequency Stabilization ≤ 10-16

Judith Olson

This dissertation details the developments of a calcium thermal beam atom interferometer designed to act as an ultra-stable frequency reference over a broad range of timescales. The obtained fractional frequency instabilities of the final apparatus reached ≤ 10−16 after 10's of seconds of averaging without the aid of vibration isolation or significant apparatus temperature stabilization. The vastly superior stability performance of this calcium system compared to other thermal atomic references was facilitated by the enormous atom numbers from the thermal beam, which can be efficiently addressed with Bord\'e-Ramsey spectroscopy on the well-studied (4s2)1S0-(4s4p)3P1 (m=0) clock transition in neutral 40Ca. This method yields interrogation laser frequency dependent interference fringes with a linewidth of 1.6 kHz. This measurement is further enhanced with an electron-shelving detection scheme used for state detection after the interferometry process, causing each excited state atom to emit many hundreds of photons in the detection region. The exceptional instability results from this atom interferometer highlight an underutilized realm of precision measurement science based on relatively simple thermal ensembles. An intuitive understanding of the Bordé-Ramsey process is presented and relevant experimental techniques explained such that this dissertation should prove useful to a broad readership.This dissertation details the developments of a calcium thermal beam atom interferometer designed to act as an ultra-stable frequency reference over a broad range of timescales. The obtained fractional frequency instabilities of the final apparatus reached ≤ 10−16 after 10's of seconds of averaging without the aid of vibration isolation or significant apparatus temperature stabilization. The vastly superior stability performance of this calcium system compared to other thermal atomic references was facilitated by the enormous atom numbers from the thermal beam, which can be efficiently addressed with Bord\'e-Ramsey spectroscopy on the well-studied (4s2)1S0-(4s4p)3P1 (m=0) clock transition in neutral 40Ca. This method yields interrogation laser frequency dependent interference fringes with a linewidth of 1.6 kHz. This measurement is further enhanced with an electron-shelving detection scheme used for state detection after the interferometry process, causing each excited state atom to emit many hundreds of photons in the detection region. The exceptional instability results from this atom interferometer highlight an underutilized realm of precision measurement science based on relatively simple thermal ensembles. An intuitive understanding of the Bordé-Ramsey process is presented and relevant experimental techniques explained such that this dissertation should prove useful to a broad readership.

Jan 1, 20190 citations

An optical frequency standard with ultracold calcium atoms

Sterr, Degenhardt, Stoehr +3 more

European Frequency and Time ForumJan 1, 20040 citations

An all-diode-laser optical frequency reference using laser-trapped calcium

Chris W. Oates, Michelle S. Stephens, Leo W. Hollberg

The 657 nm calcium intercombination line is an attractive optical frequency/length reference due to its high line Q (10/sup 12/) and insensitivity to external perturbations. In this paper we describe progress towards an all-diode-laser-based reference using laser-trapped Ca. To generate 35 mW of 423 nm trap light, we double the frequency of a 150 mW, 846 nm diode laser with a nonlinear crystal (KNbO/sub 3/) inside a resonant build-up cavity. We use this light to trap 2/spl times/10/sup 7/ atoms in a compact, magneto-optic trap. Spectroscopy of the narrow 657 nm transition is performed with a frequency-stabilized diode laser system. With the trapped atoms we have measured optical Ramsey fringes with a linewidth of 6 kHz. We discuss future improvements as well as potential performance which could achieve a fractional frequency instability of <3/spl times/10/sup -15/.The 657 nm calcium intercombination line is an attractive optical frequency/length reference due to its high line Q (10/sup 12/) and insensitivity to external perturbations. In this paper we describe progress towards an all-diode-laser-based reference using laser-trapped Ca. To generate 35 mW of 423 nm trap light, we double the frequency of a 150 mW, 846 nm diode laser with a nonlinear crystal (KNbO/sub 3/) inside a resonant build-up cavity. We use this light to trap 2/spl times/10/sup 7/ atoms in a compact, magneto-optic trap. Spectroscopy of the narrow 657 nm transition is performed with a frequency-stabilized diode laser system. With the trapped atoms we have measured optical Ramsey fringes with a linewidth of 6 kHz. We discuss future improvements as well as potential performance which could achieve a fractional frequency instability of <3/spl times/10/sup -15/.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)Nov 23, 20027 citations

A high stability optical frequency reference based on thermal calcium atoms | NIST

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A high stability optical frequency reference based on thermal calcium atoms | NIST

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