arXiv subjects

D. F. Phillips

Publications and source records attributed to D. F. Phillips.

29 records · Page 2Linked to original sources

arXiv2008

Lineshape Asymmetry for joint CPT and three photon N resonances

We show that a characteristic two photon lineshape asymmetry arises in coherent population trapping (CPT) and three photon (N) resonances because both resonances are simultaneously induced by modulation sidebands in the interrogating laser light. The N resonance is a three-photon resonance in which a two-photon Raman excitation is combined with a resonant optical pumping field. This joint CPT and N resonance can be the dominant source of lineshape distortion, with direct relevance for the operation of miniaturized atomic frequency standards. We present the results of both an experimental study and theoretical treatment of the asymmetry of the joint CPT and N resonance under conditions typical to the operation of an N resonance clock.

physics.optics↗

arXiv2006

Slow light in paraffin-coated Rb vapor cells

We present preliminary results from an experimental study of slow light in anti-relaxation-coated Rb vapor cells, and describe the construction and testing of such cells. The slow ground state decoherence rate allowed by coated cell walls leads to a dual-structured electromagnetically induced transparency (EIT) spectrum with a very narrow (<100 Hz) transparency peak on top of a broad pedestal. Such dual-structure EIT permits optical probe pulses to propagate with greatly reduced group velocity on two time scales. We discuss ongoing efforts to optimize the pulse delay in such coated cell systems.

quant-ph↗

arXiv2005

EIT and diffusion of atomic coherence

We study experimentally the effect of diffusion of Rb atoms on Electromagnetically Induced Transparency (EIT) in a buffer gas vapor cell. In particular, we find that diffusion of atomic coherence in-and-out of the laser beam plays a crucial role in determining the EIT resonance lineshape and the stored light lifetime.

quant-ph↗

arXiv2004

Bound on Lorentz- and CPT-Violating Boost Effects for the Neutron

A search for an annual variation of a daily sidereal modulation of the frequency difference between co-located ${}^{129}$Xe and ${}^{3}$He Zeeman masers sets a stringent limit on boost-dependent Lorentz and CPT violation involving the neutron, consistent with no effect at the level of 150 nHz. In the framework of the general Standard-Model Extension, the present result provides the first clean test for the fermion sector of the symmetry of spacetime under boost transformations at a level of $10^{-27}$ GeV.

physics.atom-ph↗

arXiv2004

Modulation induced frequency shifts in a CPT-based atomic clock

We investigate systematic errors associated with a common modulation technique used for phase sensitive detection of a coherent population trapping (CPT) resonance. In particular, we show that modification of the CPT resonance lineshape due to the presence of off-resonant fields leads to frequency shifts which may limit the stability of CPT-based atomic clocks. We also demonstrate that an alternative demodulation technique greatly reduces these effects.

physics.atom-ph↗

arXiv2004

Dynamic optical bistability in resonantly enhanced Raman generation

We report observations of novel dynamic behavior in resonantly-enhanced stimulated Raman scattering in Rb vapor. In particular, we demonstrate a dynamic hysteresis of the Raman scattered optical field in response to changes of the drive laser field intensity and/or frequency. This effect may be described as a dynamic form of optical bistability resulting from the formation and decay of atomic coherence. We have applied this phenomenon to the realization of an all-optical switch.

quant-ph↗

arXiv2001

Phase Coherence and Control of Stored Photonic Information

We report the demonstration of phase coherence and control for the recently developed "light storage" technique. Specifically, we use a pulsed magnetic field to vary the phase of atomic spin excitations which result from the deceleration and storing of a light pulse in warm Rb vapor. We then convert the spin excitations back into light and detect the resultant phase shift in an optical interferometric measurement. The coherent storage of photon states in matter is essential for the practical realization of many basic concepts in quantum information processing.

quant-ph↗

arXiv2001

Testing Lorentz and CPT symmetry with hydrogen masers

We present details from a recent test of Lorentz and CPT symmetry using hydrogen masers. We have placed a new limit on Lorentz and CPT violation of the proton in terms of a recent standard model extension by placing a bound on sidereal variation of the F = 1 Zeeman frequency in hydrogen. Here, the theoretical standard model extension is reviewed. The operating principles of the maser and the double resonance technique used to measure the Zeeman frequency are discussed. The characterization of systematic effects is described, and the method of data analysis is presented. We compare our result to other recent experiments, and discuss potential steps to improve our measurement.

physics.atom-ph↗

arXiv2000

Storage of light in atomic vapor

We report an experiment in which a light pulse is decelerated and trapped in a vapor of Rb atoms, stored for a controlled period of time, and then released on demand. We accomplish this storage of light by dynamically reducing the group velocity of the light pulse to zero, so that the coherent excitation of the light is reversibly mapped into a collective Zeeman (spin) coherence of the Rb vapor.

quant-ph↗

arXiv2000

Limit on Lorentz and CPT Violation of the Proton Using a Hydrogen Maser

We present a new measurement constraining Lorentz and CPT violation of the proton using a hydrogen maser double resonance technique. A search for hydrogen Zeeman frequency variations with a period of the sidereal day (23.93 h) sets a clean limit on violation of Lorentz and CPT symmetry of the proton at the 10^{-27} GeV level.

physics.atom-ph↗

arXiv2000

Double resonance frequency shift in a hydrogen maser

We use the dressed atom formalism to calculate the frequency shift in a hydrogen maser induced by applied radiation near the Zeeman frequency, and find excellent agreement with a previous calculation made in the bare atom basis. The maser oscillates on the Delta_F = 1, Delta_m_F = 0 hyperfine transition, while the applied field is swept through the F = 1, Delta_m_F = \pm 1 Zeeman resonance. We determine the effect of the applied field on the Zeeman levels using the dressed atom picture, and then calculate the maser frequency shift by coupling the dressed states to the microwave cavity. Qualitatively, the dressed-atom analysis gives a new and simpler physical interpretation of this double resonance process, which has applications in precision hydrogen Zeeman spectroscopy, e.g., in fundamental symmetry tests.

physics.atom-ph↗