Fractional frequency instability in the 10{sup -14} range with a thermal beam optical frequency reference

Journal Article · Mon Feb 15 00:00:00 EST 2010 · Journal of the Optical Society of America. Part B, Optical Physics

DOI:https://doi.org/10.1364/JOSAB.27.000277· OSTI ID:22046838

McFerran, John J; Luiten, Andre N ^[1]

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1. School of Physics, University of Western Australia, 35 Stirling Highway, Crawley 6009, W.A. (Australia)

We demonstrate a means of increasing the signal-to-noise ratio in a Ramsey-Borde interferometer with spatially separated oscillatory fields on a thermal atomic beam. The {sup 1}S{sub 0}{r_reversible}{sup 3}P{sub 1} intercombination line in neutral {sup 40}Ca is used as a frequency discriminator, with an extended cavity diode laser at 423 nm probing the ground state population after a Ramsey-Borde sequence of 657 nm light-field interactions with the atoms. Evaluation of the instability of the Ca frequency reference is carried out by comparison with (i) a hydrogen-maser and (ii) a cryogenic sapphire oscillator. In the latter case the Ca reference exhibits a square-root {Lambda} variance of 9.2x10{sup -14} at 1 s and 2.0x10{sup -14} at 64 s. This is an order-of-magnitude improvement for optical beam frequency references, to our knowledge. The shot noise of the readout fluorescence produces a limiting square-root {Lambda} variance of 7x10{sup -14}/{radical}({tau}), highlighting the potential for improvement. This work demonstrates the feasibility of a portable frequency reference in the optical domain with 10{sup -14} range frequency instability.

• OSTI ID: 22046838
• Journal Information: Journal of the Optical Society of America. Part B, Optical Physics, Vol. 27, Issue 2; Other Information: (c) 2010 Optical Society of America; Country of input: International Atomic Energy Agency (IAEA); ISSN 0740-3224
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOMIC BEAMS
CALCIUM 40
COMPARATIVE EVALUATIONS
FLUORESCENCE
GROUND STATES
HYDROGEN
INSTABILITY
INTERFEROMETERS
LASER CAVITIES
MASERS
NOISE
OSCILLATORS
PHOTON-ATOM COLLISIONS
READOUT SYSTEMS
RESONATORS
SAPPHIRE
SEMICONDUCTOR LASERS
SIGNAL-TO-NOISE RATIO
VISIBLE RADIATION