Physical Review Letters

Zero-Field Level-Crossing Resonances in Optically Pumped 23S1 He4

Robert E. Slocum

Published Dec 18, 1972• 15 citations

Abstract

Parametric resonances associated with zero-field level crossings of the ${2}^{3}{S}_{1}$ level of ${\mathrm{He}}^{4}$ have been investigated using transverse optical pumping. A steady-state technique based on the $n=0$, $p=0$ resonance (Hanle effect) is used to measure spin-state lifetimes and determine the dependence of the thermal relaxation time on the state of the active helium discharge. The $n=0$, $p=1$ resonance is quite strong and suitable for measuring weak magnetic fields. A sensitivity of 1.0 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}8}$ G is demonstrated for this measurement technique.

DOI: 10.1103/physrevlett.29.1642

Related papers

Hanle Effect in 2P1 Helium

Edward S. Fry, W. Williams

Physical ReviewJul 5, 196914 citations

Hanle Effect In The Singlet-2p State Of Helium.

Edward S. Fry

Jan 1, 19690 citations

Optical Pumping of Helium in the S13 Metastable State

F. D. Colegrove, P. A. Franken

Physical ReviewJul 15, 1960118 citations

The zero-field resonance in optical pumping experiments

B. W. James, William J. Tango

European Journal of PhysicsJul 10, 20200 citations

The Hanle effect

L. N. Novikov, G. V. Skrotskiǐ, G. I. Solomakho

Soviet Physics UspekhiApr 30, 197519 citations

Measurements of Lowest-S-State Lifetimes of Gallium, Indium, and Thalium

Michael Norton, Alan C. Gallagher

Physical Review AMar 1, 197134 citations

Physical Review Letters

Zero-Field Level-Crossing Resonances in Optically Pumped 23S1 He4

Robert E. Slocum

Published Dec 18, 1972• 15 citations

Publisher

Abstract

Parametric resonances associated with zero-field level crossings of the

{2}^{3}{S}_{1}

level of

{\mathrm{He}}^{4}

have been investigated using transverse optical pumping. A steady-state technique based on the

n=0

p=0

resonance (Hanle effect) is used to measure spin-state lifetimes and determine the dependence of the thermal relaxation time on the state of the active helium discharge. The

n=0

p=1

resonance is quite strong and suitable for measuring weak magnetic fields. A sensitivity of 1.0 \ifmmode\times\else\texttimes\fi{}

{10}^{\ensuremath{-}8}

G is demonstrated for this measurement technique.

DOI: 10.1103/physrevlett.29.1642

Related papers

Hanle Effect in 2P1 Helium

Edward S. Fry, W. Williams

The oscillator strength for the resonance ($1^{1}S\ensuremath{-}2^{1}P$) transition in atomic helium has been determined from a measurement of the lifetime of the $2^{1}P$ state. This lifetime was obtained using a modified zero-field level crossing (Hanle) method. The scattering sample was a thermal velocity beam of $2^{1}S$ metastable atoms. Resonant 2-\ensuremath{\mu} ($2^{1}S\ensuremath{-}2^{1}P$) radiation is absorbed by the $2^{1}S$ atoms, which are excited to the $2^{1}P$ state. This state then primarily decays to the ground $1^{1}S$ state with the emission of resonance (584 \AA{}) radiation. The lifetime of the $2^{1}P$ state was determined from measurements of the magnetic-field dependence of the angular distribution of the 584 \AA{} intensity. This new technique eliminates the problem of constructing a vacuum ultraviolet resonance lamp. The measured lifetime $\ensuremath{\tau} (2^{1}P)$ is (5.63 \ifmmode\pm\else\textpm\fi{} 0.22) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ sec. The resulting absorption oscillator strength for the resonance transition is 0.273 \ifmmode\pm\else\textpm\fi{} 0.011. This oscillator strength agrees with the theoretical value.The oscillator strength for the resonance ($1^{1}S\ensuremath{-}2^{1}P$) transition in atomic helium has been determined from a measurement of the lifetime of the $2^{1}P$ state. This lifetime was obtained using a modified zero-field level crossing (Hanle) method. The scattering sample was a thermal velocity beam of $2^{1}S$ metastable atoms. Resonant 2-\ensuremath{\mu} ($2^{1}S\ensuremath{-}2^{1}P$) radiation is absorbed by the $2^{1}S$ atoms, which are excited to the $2^{1}P$ state. This state then primarily decays to the ground $1^{1}S$ state with the emission of resonance (584 \AA{}) radiation. The lifetime of the $2^{1}P$ state was determined from measurements of the magnetic-field dependence of the angular distribution of the 584 \AA{} intensity. This new technique eliminates the problem of constructing a vacuum ultraviolet resonance lamp. The measured lifetime $\ensuremath{\tau} (2^{1}P)$ is (5.63 \ifmmode\pm\else\textpm\fi{} 0.22) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ sec. The resulting absorption oscillator strength for the resonance transition is 0.273 \ifmmode\pm\else\textpm\fi{} 0.011. This oscillator strength agrees with the theoretical value.

Physical ReviewJul 5, 196914 citations

Hanle Effect In The Singlet-2p State Of Helium.

Edward S. Fry

The oscillator strength for the resonance (11S-21P) transition in atomic helium has been determined from a measurement of the lifetime of the 2^ state.This life time was obtained using a modified zero field level crossing (Hanle) method.The scattering sample was a thermal velocity beam of 2^8 metastable atoms.Resonant 2 micron (218-2^2) radiation is absorbed by the 21S atoms, which are excited to the 2^P state.This state then primarily decays to the ground 1^8 state with the emission of resonance ($84A) radiation.The lifetime of the 21P state was determined from measurements of the magnetic field dependence of the 584Â intensity.This new technique eliminates the problem of constructing a vacuum ultra violet resonance lamp.The measured lifetime t(2 P) is (5.69 ±0.23) x Id"10 sec.The resulting absorption oscillator strength for the resonance transition is 0.270 ±0.011.This oscillator strength agrees with tie theoretical value.The oscillator strength for the resonance (11S-21P) transition in atomic helium has been determined from a measurement of the lifetime of the 2^ state.This life time was obtained using a modified zero field level crossing (Hanle) method.The scattering sample was a thermal velocity beam of 2^8 metastable atoms.Resonant 2 micron (218-2^2) radiation is absorbed by the 21S atoms, which are excited to the 2^P state.This state then primarily decays to the ground 1^8 state with the emission of resonance ($84A) radiation.The lifetime of the 21P state was determined from measurements of the magnetic field dependence of the 584Â intensity.This new technique eliminates the problem of constructing a vacuum ultra violet resonance lamp.The measured lifetime t(2 P) is (5.69 ±0.23) x Id"10 sec.The resulting absorption oscillator strength for the resonance transition is 0.270 ±0.011.This oscillator strength agrees with tie theoretical value.

Jan 1, 19690 citations

Optical Pumping of Helium in the S13 Metastable State

F. D. Colegrove, P. A. Franken

The alignment of ${\mathrm{He}}^{4}$ atoms in the ( $n=2$ , metastable) $^{3}S_{1}$ state is described. Metastable atoms are produced by an rf discharge in a glass tube containing a few mm of pure helium, and the one micron pumping light ($2^{3}P\ensuremath{-}2^{3}S$) is provided by a helium lamp. A resonance signal is obtained from radio frequency disorientation by monitoring the transmitted pumping light. The double maximum line shape of this signal for strong rf magnetic fields is discussed. Included also is a discussion of the angular dependence of the signal when unpolarized light is used and an explanation of the inversion of the resonance signal for certain densities of the metastable helium atoms.The measured relaxation time of the oriented metastable atoms in the discharge is about 2.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ second and the pumping time is about a millisecond. A method is proposed and initial measurements are given for the cross section for destruction of metastable helium atoms by collision with foreign gas atoms. The application of optical pumping in helium to the measurement of weak magnetic fields is also discussed.The alignment of ${\mathrm{He}}^{4}$ atoms in the ($n=2$, metastable) $^{3}S_{1}$ state is described. Metastable atoms are produced by an rf discharge in a glass tube containing a few mm of pure helium, and the one micron pumping light ($2^{3}P\ensuremath{-}2^{3}S$) is provided by a helium lamp. A resonance signal is obtained from radio frequency disorientation by monitoring the transmitted pumping light. The double maximum line shape of this signal for strong rf magnetic fields is discussed. Included also is a discussion of the angular dependence of the signal when unpolarized light is used and an explanation of the inversion of the resonance signal for certain densities of the metastable helium atoms.The measured relaxation time of the oriented metastable atoms in the discharge is about 2.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ second and the pumping time is about a millisecond. A method is proposed and initial measurements are given for the cross section for destruction of metastable helium atoms by collision with foreign gas atoms. The application of optical pumping in helium to the measurement of weak magnetic fields is also discussed.

Physical ReviewJul 15, 1960118 citations

The zero-field resonance in optical pumping experiments

B. W. James, William J. Tango

Abstract It is common for senior physics students at many universities to perform optical pumping experiments using a rubidium cell in an integrated apparatus. Such experiments provide an encounter with atomic structure in the context of a standard technique of modern atomic physics. Typically, students investigate radiofrequency resonances between Zeeman levels and measure hyperfine splitting. Despite its pivotal role in aligning the apparatus the so-called zero-field resonance is usually not investigated in such experiments. However it is instructive to look more closely at this phenomenon. We show that it is a consequence of a residual transverse magnetic field that is the result of the inability to align precisely the optical axis of the apparatus in the local N – S direction. The measured width and depth of the resonance-like minimum in transmission is found to be consistent with a very small relaxation rate for the rubidium atoms. In an appendix we show further that the measurements compare well with theory for the Hanle effect in the ground state for an arbitrary magnetic field direction relative to the optical axis of the experiment.Abstract It is common for senior physics students at many universities to perform optical pumping experiments using a rubidium cell in an integrated apparatus. Such experiments provide an encounter with atomic structure in the context of a standard technique of modern atomic physics. Typically, students investigate radiofrequency resonances between Zeeman levels and measure hyperfine splitting. Despite its pivotal role in aligning the apparatus the so-called zero-field resonance is usually not investigated in such experiments. However it is instructive to look more closely at this phenomenon. We show that it is a consequence of a residual transverse magnetic field that is the result of the inability to align precisely the optical axis of the apparatus in the local N – S direction. The measured width and depth of the resonance-like minimum in transmission is found to be consistent with a very small relaxation rate for the rubidium atoms. In an appendix we show further that the measurements compare well with theory for the Hanle effect in the ground state for an arbitrary magnetic field direction relative to the optical axis of the experiment.

European Journal of PhysicsJul 10, 20200 citations

The Hanle effect

L. N. Novikov, G. V. Skrotskiǐ, G. I. Solomakho

The history of the discovery, study, and explanation of the effect discovered fifty years ago by the German physicist Hanle and its development and generalization by the French school of physicists led by Kastler are described. The effect is observed optically in an increase in the degree of depolarization of the resonance fluorescence. It is studied in the range of magnetic fields in which the Zeeman splitting of the atomic magnetic sublevels does not exceed the level widths determined by thermal relaxation mechanisms and electromagnetic interaction. It is a direct optical manifestation of interference of degenerate atomic states and is intimately connected with the conservation law for the angular momentum of the photon-atom system. In the review, different applications of the effect to the measurement of mean lifetimes, linewidths, and Stark splitting constants of atoms in excited states are given. The resonance scattering of light by atoms in the ground state in a weak magnetic field is considered in detail—in particular, in the presence of radio-frequency magnetic fields oriented in different ways. The different possible types of parametric resonances in one or two radio-frequency fields for arbitrary orientation of the constant magnetic field are interpreted as the effect of crossing of the levels of an atom that is dressed by the radio-frequency field. Applications of the effect in the quantum magnetometry of ultraweak fields (down to 10-10 Oe) are examined.The history of the discovery, study, and explanation of the effect discovered fifty years ago by the German physicist Hanle and its development and generalization by the French school of physicists led by Kastler are described. The effect is observed optically in an increase in the degree of depolarization of the resonance fluorescence. It is studied in the range of magnetic fields in which the Zeeman splitting of the atomic magnetic sublevels does not exceed the level widths determined by thermal relaxation mechanisms and electromagnetic interaction. It is a direct optical manifestation of interference of degenerate atomic states and is intimately connected with the conservation law for the angular momentum of the photon-atom system. In the review, different applications of the effect to the measurement of mean lifetimes, linewidths, and Stark splitting constants of atoms in excited states are given. The resonance scattering of light by atoms in the ground state in a weak magnetic field is considered in detail—in particular, in the presence of radio-frequency magnetic fields oriented in different ways. The different possible types of parametric resonances in one or two radio-frequency fields for arbitrary orientation of the constant magnetic field are interpreted as the effect of crossing of the levels of an atom that is dressed by the radio-frequency field. Applications of the effect in the quantum magnetometry of ultraweak fields (down to 10-10 Oe) are examined.

Soviet Physics UspekhiApr 30, 197519 citations

Measurements of Lowest-S-State Lifetimes of Gallium, Indium, and Thalium

Michael Norton, Alan C. Gallagher

The lifetimes of the gallium $5^{2}S_{\frac{1}{2}}$ state, the indium $6^{2}S_{\frac{1}{2}}$ state, and the thallium $7^{2}S_{\frac{1}{2}}$ state were measured using the zero-field level-crossing (Hanle-effect) technique. The life-times obtained were (6.8\ifmmode\pm\else\textpm\fi{}0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$, (7.0\ifmmode\pm\else\textpm\fi{}0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$, and (7.45\ifmmode\pm\else\textpm\fi{}0.2) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$ sec, respectively. Anomalous contributions to the level-crossing signals, from the wavelength dependence of the exciting light intensity and self-absorption by the fluorescing atomic beam, were investigated in detail.The lifetimes of the gallium $5^{2}S_{\frac{1}{2}}$ state, the indium $6^{2}S_{\frac{1}{2}}$ state, and the thallium $7^{2}S_{\frac{1}{2}}$ state were measured using the zero-field level-crossing (Hanle-effect) technique. The life-times obtained were (6.8\ifmmode\pm\else\textpm\fi{}0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$, (7.0\ifmmode\pm\else\textpm\fi{}0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$, and (7.45\ifmmode\pm\else\textpm\fi{}0.2) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$ sec, respectively. Anomalous contributions to the level-crossing signals, from the wavelength dependence of the exciting light intensity and self-absorption by the fluorescing atomic beam, were investigated in detail.

Physical Review AMar 1, 197134 citations

Parametric resonances associated with zero-field level crossings of the

{2}^{3}{S}_{1}

level of

{\mathrm{He}}^{4}

have been investigated using transverse optical pumping. A steady-state technique based on the

n=0

p=0

resonance (Hanle effect) is used to measure spin-state lifetimes and determine the dependence of the thermal relaxation time on the state of the active helium discharge. The

n=0

p=1

resonance is quite strong and suitable for measuring weak magnetic fields. A sensitivity of 1.0 \ifmmode\times\else\texttimes\fi{}

{10}^{\ensuremath{-}8}

G is demonstrated for this measurement technique.

The oscillator strength for the resonance ($1^{1}S\ensuremath{-}2^{1}P$) transition in atomic helium has been determined from a measurement of the lifetime of the

2^{1}P

state. This lifetime was obtained using a modified zero-field level crossing (Hanle) method. The scattering sample was a thermal velocity beam of

2^{1}S

metastable atoms. Resonant 2-\ensuremath{\mu} ($2^{1}S\ensuremath{-}2^{1}P$) radiation is absorbed by the

2^{1}S

atoms, which are excited to the

2^{1}P

state. This state then primarily decays to the ground

1^{1}S

state with the emission of resonance (584 \AA{}) radiation. The lifetime of the

2^{1}P

state was determined from measurements of the magnetic-field dependence of the angular distribution of the 584 \AA{} intensity. This new technique eliminates the problem of constructing a vacuum ultraviolet resonance lamp. The measured lifetime $\ensuremath{\tau} (2^{1}P)$ is (5.63 \ifmmode\pm\else\textpm\fi{} 0.22) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}10}$ sec. The resulting absorption oscillator strength for the resonance transition is 0.273 \ifmmode\pm\else\textpm\fi{} 0.011. This oscillator strength agrees with the theoretical value.

The alignment of

{\mathrm{He}}^{4}

atoms in the (

n=2

, metastable)

^{3}S_{1}

state is described. Metastable atoms are produced by an rf discharge in a glass tube containing a few mm of pure helium, and the one micron pumping light ($2^{3}P\ensuremath{-}2^{3}S$) is provided by a helium lamp. A resonance signal is obtained from radio frequency disorientation by monitoring the transmitted pumping light. The double maximum line shape of this signal for strong rf magnetic fields is discussed. Included also is a discussion of the angular dependence of the signal when unpolarized light is used and an explanation of the inversion of the resonance signal for certain densities of the metastable helium atoms.The measured relaxation time of the oriented metastable atoms in the discharge is about 2.5\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}4}$ second and the pumping time is about a millisecond. A method is proposed and initial measurements are given for the cross section for destruction of metastable helium atoms by collision with foreign gas atoms. The application of optical pumping in helium to the measurement of weak magnetic fields is also discussed.

The lifetimes of the gallium

5^{2}S_{\frac{1}{2}}

state, the indium

6^{2}S_{\frac{1}{2}}

state, and the thallium

7^{2}S_{\frac{1}{2}}

state were measured using the zero-field level-crossing (Hanle-effect) technique. The life-times obtained were (6.8\ifmmode\pm\else\textpm\fi{}0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$, (7.0\ifmmode\pm\else\textpm\fi{}0.3) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$, and (7.45\ifmmode\pm\else\textpm\fi{}0.2) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}9}$ sec, respectively. Anomalous contributions to the level-crossing signals, from the wavelength dependence of the exciting light intensity and self-absorption by the fluorescing atomic beam, were investigated in detail.