TY - GEN
T1 - Distributed cavity phase and the associated power dependence
AU - Li, Ruoxin
AU - Gibble, Kurt
PY - 2005
Y1 - 2005
N2 - We discuss the power dependence of distributed cavity phase errors for cylindrical TE011 cavities in laser-cooled atomic fountain clocks. The azimuthally symmetric phase variations produce a surprisingly large distributed cavity phase error for two 2π, 4π, and 6π pulses. This is due to the correlation between the transverse variation of the Rabi frequency over the cavity aperture and a quadratic density variation of the atomic sample, along with the symmetry of the longitudinal phase variation in the cavity. We show that the large azimuthally symmetric fields and phase shifts near the walls of the endcap holes produce very small errors at optimal power for a uniform wall resistance. We also show the power variation for higher order azimuthal variations m=1, 2, and 4. These may be caused by fountain tilts, non-uniform detection of atoms, and asymmetries in the laser trapping and cooling of the atoms. We demonstrate that distributed cavity phase errors in physical cavities may have no variation with the microwave power. A combination of rigorous calculations of cavity losses, measurements of power dependence, the atomic distributions, and fountain tilts, and electrical measurements that show the lower limit of the cavity Q and the cavity symmetry, should provide stringent limits on distributed cavity phase errors for current atomic clocks.
AB - We discuss the power dependence of distributed cavity phase errors for cylindrical TE011 cavities in laser-cooled atomic fountain clocks. The azimuthally symmetric phase variations produce a surprisingly large distributed cavity phase error for two 2π, 4π, and 6π pulses. This is due to the correlation between the transverse variation of the Rabi frequency over the cavity aperture and a quadratic density variation of the atomic sample, along with the symmetry of the longitudinal phase variation in the cavity. We show that the large azimuthally symmetric fields and phase shifts near the walls of the endcap holes produce very small errors at optimal power for a uniform wall resistance. We also show the power variation for higher order azimuthal variations m=1, 2, and 4. These may be caused by fountain tilts, non-uniform detection of atoms, and asymmetries in the laser trapping and cooling of the atoms. We demonstrate that distributed cavity phase errors in physical cavities may have no variation with the microwave power. A combination of rigorous calculations of cavity losses, measurements of power dependence, the atomic distributions, and fountain tilts, and electrical measurements that show the lower limit of the cavity Q and the cavity symmetry, should provide stringent limits on distributed cavity phase errors for current atomic clocks.
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U2 - 10.1109/FREQ.2005.1573909
DO - 10.1109/FREQ.2005.1573909
M3 - Conference contribution
AN - SCOPUS:33846585603
SN - 0780390539
SN - 9780780390539
T3 - Proceedings of the IEEE International Frequency Control Symposium and Exposition
SP - 99
EP - 104
BT - 2005 Joint IEEE International Frequency Controlo Symposium (FCS) and Precise Tome and Time INterval (PTTI) Systems and Applications Meeting
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2005 Joint IEEE International Frequency Control Symposium (FCS) and Precise Time and Time Interval (PTTI) Systems and Applications Meeting
Y2 - 29 August 2005 through 31 August 2005
ER -