We have used two sets of opposite circularly polarized traveling wave pulses separated in time to establish, and subsequently rephase, a spatially modulated coherence between the magnetic sublevels of the $F=3$ ground state in Doppler broadened ${}^{85}\mathrm{Rb}$ vapor. The rephasing results in a magnetic grating echo whose duration is an accurate measure of the velocity distribution. We demonstrate that the time scale of the experiment is determined solely by the transit time of atoms across the laser beam. The shortening of the lifetime due to a perturber (Ar) allows us to infer the Rb-Ar velocity changing collision cross section.We have used two sets of opposite circularly polarized traveling wave pulses separated in time to establish, and subsequently rephase, a spatially modulated coherence between the magnetic sublevels of the $F=3$ ground state in Doppler broadened ${}^{85}\mathrm{Rb}$ vapor. The rephasing results in a magnetic grating echo whose duration is an accurate measure of the velocity distribution. We demonstrate that the time scale of the experiment is determined solely by the transit time of atoms across the laser beam. The shortening of the lifetime due to a perturber (Ar) allows us to infer the Rb-Ar velocity changing collision cross section.

Physical Review ANov 1, 199813 citations

Experiments With Magnetic Grating Echoes In Trapped Atoms

Anantharaman Kumarakrishnan, S. B. Cahn, Unyob Shim +1 more

Quantum Electronics and Laser Science ConferenceJan 1, 19970 citations

Transmittance Spectrum for a Doppler-broadened Rubidium Vapor Cell

Min Jeong Seo, Heung‐Ryoul Noh

New Physics Sae MulliAug 31, 20100 citations

Magnetic grating echo from room temperature Rb atoms

Anantharaman Kumarakrishnan, S. B. Cahn, Unyob Shim +1 more

We have initiated a new class of coherent transient experiments with Doppler-broadened atoms confined in a vapor cell. A spatially modulated coherence is created between magnetic sublevels of the F=3 ground state of /sup 85/Rb by a standing pulse. This pulse consists of two opposite circularly polarized traveling waves with wave vectors K/sub 1/ and K/sub 2/ at a small angle /spl theta/. The coherence grating is probed by the application of a readout pulse along K/sub 2/. The resulting coherent emission along K/sub 1/ is detected by a heterodyne technique.We have initiated a new class of coherent transient experiments with Doppler-broadened atoms confined in a vapor cell. A spatially modulated coherence is created between magnetic sublevels of the F=3 ground state of /sup 85/Rb by a standing pulse. This pulse consists of two opposite circularly polarized traveling waves with wave vectors K/sub 1/ and K/sub 2/ at a small angle /spl theta/. The coherence grating is probed by the application of a readout pulse along K/sub 2/. The resulting coherent emission along K/sub 1/ is detected by a heterodyne technique.

Quantum Electronics and Laser Science ConferenceJun 7, 19960 citations

Properties of magnetic sublevel coherences for precision measurements

I. Y. Chan, A. Andreyuk, Scott Beattie +4 more

We have developed a theoretical description of the evolution of ground state coherences between magnetic sublevels in Rb vapor in the presence of a magnetic field along an arbitrary direction. This formalism uses a rotation matrix approach to describe the evolution of coherences created by two traveling wave laser pulses with orthogonal polarizations. The effect of a magnetic field can be described as a time-dependent rotation of the atomic system about the quantization axis. Predictions based on this theoretical formalism for the functional form of Larmor oscillations in a magnetic field are studied using a coherent transient effect known as magnetic grating free induction decay (MGFID) using room temperature vapor and laser cooled atoms. We find the theoretical predictions to be in excellent agreement with data. The velocity distribution of the cold sample measured from the dephasing time of the MGFID in the absence of magnetic fields is in agreement with the sample temperature obtained by imaging the ballistic expansion of the trapped cloud. By using rate equations to model atomic coherences, it is also possible to predict the evolution of magnetic grating echoes (MGE) in a magnetic field. We compare these predictions with experiments from cold atoms and discuss applications of the MGFID and MGE that relate to a precision measurement of the atomic $g$ factor ratio using $^{85}\mathrm{Rb}$ and $^{87}\mathrm{Rb}$ isotopes.We have developed a theoretical description of the evolution of ground state coherences between magnetic sublevels in Rb vapor in the presence of a magnetic field along an arbitrary direction. This formalism uses a rotation matrix approach to describe the evolution of coherences created by two traveling wave laser pulses with orthogonal polarizations. The effect of a magnetic field can be described as a time-dependent rotation of the atomic system about the quantization axis. Predictions based on this theoretical formalism for the functional form of Larmor oscillations in a magnetic field are studied using a coherent transient effect known as magnetic grating free induction decay (MGFID) using room temperature vapor and laser cooled atoms. We find the theoretical predictions to be in excellent agreement with data. The velocity distribution of the cold sample measured from the dephasing time of the MGFID in the absence of magnetic fields is in agreement with the sample temperature obtained by imaging the ballistic expansion of the trapped cloud. By using rate equations to model atomic coherences, it is also possible to predict the evolution of magnetic grating echoes (MGE) in a magnetic field. We compare these predictions with experiments from cold atoms and discuss applications of the MGFID and MGE that relate to a precision measurement of the atomic $g$ factor ratio using $^{85}\mathrm{Rb}$ and $^{87}\mathrm{Rb}$ isotopes.

Physical Review ASep 17, 200811 citations

Transmittance Spectrum for a Doppler-broadened Rubidium Vapor Cell

서민정, NohHeungRyoul

New Physics Sae MulliJan 1, 20100 citations

F=3

ground state in Doppler broadened

{}^{85}\mathrm{Rb}

vapor. The rephasing results in a magnetic grating echo whose duration is an accurate measure of the velocity distribution. We demonstrate that the time scale of the experiment is determined solely by the transit time of atoms across the laser beam. The shortening of the lifetime due to a perturber (Ar) allows us to infer the Rb-Ar velocity changing collision cross section.

g

factor ratio using

^{85}\mathrm{Rb}

and

^{87}\mathrm{Rb}

isotopes.