Polarization of $sup 4$He(2$sup 3$S$sub 1$) by optically pumped Rb

We have investigated high-density Rb optical pumping in polarized $^{3}\mathrm{He}$ targets and present measurements of collisional relaxation rates and studies of diffusion-driven wall relaxation of the Rb polarization. We show that a boundary layer resides in the vicinity of the cell walls within which a polarization gradient is established by diffusion. Absorption of the incident laser radiation within this layer leads to a striking decrease in optical-pumping efficiency for resonant light but has little effect for off-resonant light. Our theory introduces polarization-dependent slowing of optical pumping rates due to the Rb nuclear spin. We have observed a strong frequency dependence of the optical-pumping efficiency, consistent with our theoretical predictions. We report the following rate constants for collisional relaxation of Rb polarization: due to Rb (${\mathit{k}}_{\mathrm{Rb}\mathrm{\ensuremath{-}}\mathrm{Rb}}$=8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$ /s), due to ${\mathrm{N}}_{2}$ (${\mathit{k}}_{\mathrm{N}2\mathrm{\ensuremath{-}}}$Rb=8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$ ${\mathrm{cm}}^{3}$ /s), and due to $^{3}\mathrm{He}$ , an upper limit of ( ${\mathit{k}}^{3}$ He-Rb\ensuremath{\le}2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$ ${\mathrm{cm}}^{3}$ /s). The data and model presented are used to predict laser power and intensity requirements for high-density polarized $^{3}\mathrm{He}$ targets.We have investigated high-density Rb optical pumping in polarized $^{3}\mathrm{He}$ targets and present measurements of collisional relaxation rates and studies of diffusion-driven wall relaxation of the Rb polarization. We show that a boundary layer resides in the vicinity of the cell walls within which a polarization gradient is established by diffusion. Absorption of the incident laser radiation within this layer leads to a striking decrease in optical-pumping efficiency for resonant light but has little effect for off-resonant light. Our theory introduces polarization-dependent slowing of optical pumping rates due to the Rb nuclear spin. We have observed a strong frequency dependence of the optical-pumping efficiency, consistent with our theoretical predictions. We report the following rate constants for collisional relaxation of Rb polarization: due to Rb (${\mathit{k}}_{\mathrm{Rb}\mathrm{\ensuremath{-}}\mathrm{Rb}}$=8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{3}$/s), due to ${\mathrm{N}}_{2}$ (${\mathit{k}}_{\mathrm{N}2\mathrm{\ensuremath{-}}}$Rb=8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$ ${\mathrm{cm}}^{3}$/s), and due to $^{3}\mathrm{He}$, an upper limit of (${\mathit{k}}^{3}$He-Rb\ensuremath{\le}2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$ ${\mathrm{cm}}^{3}$/s). The data and model presented are used to predict laser power and intensity requirements for high-density polarized $^{3}\mathrm{He}$ targets.

Physical Review AMay 1, 1994104 citations

Photoionization of He(n $sup 1$ $sup 3$ P) atoms excited by polarized lightPhotoionization of He(n$sup 1$ $sup 3$P) atoms excited by polarized light

V. L. Jacobs

Physical Review LettersJun 24, 19740 citations

Three-dimensional imaging of spin polarization of alkali-metal vapor in optical pumping cells

Albert R. Young, Stephan Appelt, Andrei Ben-Amar Baranga +2 more

We present detailed images of the Rb polarization in a high-pressure optical pumping cell. Images taken at high magnetic field strengths (≈37 G) yield precise information on the relative occupation probability of the hyperfine Zeeman sublevels. Low-field (⩽4 G) images yield very high resolution (less than 1 mm) maps of the spatial distribution of the Rb polarization. For optical pumping in the presence of high-pressure buffer gases, the measured populations of the hyperfine magnetic sublevels are shown to be well described by a spin temperature, even though the Rb–Rb spin exchange rate is much smaller than the rates of optical pumping or electron-randomizing Rb–Xe collisions in the buffer gas.We present detailed images of the Rb polarization in a high-pressure optical pumping cell. Images taken at high magnetic field strengths (≈37 G) yield precise information on the relative occupation probability of the hyperfine Zeeman sublevels. Low-field (⩽4 G) images yield very high resolution (less than 1 mm) maps of the spatial distribution of the Rb polarization. For optical pumping in the presence of high-pressure buffer gases, the measured populations of the hyperfine magnetic sublevels are shown to be well described by a spin temperature, even though the Rb–Rb spin exchange rate is much smaller than the rates of optical pumping or electron-randomizing Rb–Xe collisions in the buffer gas.

Applied Physics LettersJun 9, 199737 citations

Polarization of

sup 4

He(2

sup 3

sub 1

) by optically pumped Rb

We have investigated high-density Rb optical pumping in polarized

^{3}\mathrm{He}

targets and present measurements of collisional relaxation rates and studies of diffusion-driven wall relaxation of the Rb polarization. We show that a boundary layer resides in the vicinity of the cell walls within which a polarization gradient is established by diffusion. Absorption of the incident laser radiation within this layer leads to a striking decrease in optical-pumping efficiency for resonant light but has little effect for off-resonant light. Our theory introduces polarization-dependent slowing of optical pumping rates due to the Rb nuclear spin. We have observed a strong frequency dependence of the optical-pumping efficiency, consistent with our theoretical predictions. We report the following rate constants for collisional relaxation of Rb polarization: due to Rb (${\mathit{k}}_{\mathrm{Rb}\mathrm{\ensuremath{-}}\mathrm{Rb}}$=8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$

{\mathrm{cm}}^{3}

/s), due to

{\mathrm{N}}_{2}

(${\mathit{k}}_{\mathrm{N}2\mathrm{\ensuremath{-}}}$Rb=8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$

{\mathrm{cm}}^{3}

/s), and due to

^{3}\mathrm{He}

, an upper limit of (

{\mathit{k}}^{3}

He-Rb\ensuremath{\le}2\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}18}$

{\mathrm{cm}}^{3}

/s). The data and model presented are used to predict laser power and intensity requirements for high-density polarized

^{3}\mathrm{He}

targets.

Photoionization of He(n

sup 1

sup 3

P) atoms excited by polarized light