2018 Conference on Precision Electromagnetic Measurements (CPEM 2018), 2018
A novel single pressure refractive index gas thermometry(SPRIGT) allows the determination of ther... more A novel single pressure refractive index gas thermometry(SPRIGT) allows the determination of thermodynamic temperature of helium gas filled in quasi-spherical microwave cavity resonator(QMCR) by combination of microwave measurements, temperature and pressure control. A long-term temperature stability better than O.2mK is demanded for the QMCR from 5K to 24.5561 K. The uncertainty below 4ppm for pressure needs to precisely control the oscillation of temperature along the gas line. Microwave resonance frequency measurement in QMCR should be better than 2ppb. To meet these requirements, SPRIGT has been built in China and the first run experimental data was analysis in this paper.
In this article, we present an analysis of the stability of optical lattices. Starting with the s... more In this article, we present an analysis of the stability of optical lattices. Starting with the study of an unstable optical lattice, we establish a necessary and sufficient condition for intrinsic phase stability and discuss two practical solutions to fulfill this condition, namely, minimal and folded optical lattices. We then present a particular example of two-dimensional folded optical lattice, which has the advantages of being symmetric, possessing power recycling, and having a convenient geometry. We used this lattice for laser collimation of a continuous cesium beam in a fountain geometry.
We propose a new simple approximate solution to the two-state rate equation model for analyzing d... more We propose a new simple approximate solution to the two-state rate equation model for analyzing decay signals of saturation cavity ring-down spectrometry in the adiabatic and low-saturation regime. It helps obtain baseline-immune Doppler-free spectra for hyperfine transitions and linear absorption coefficients of a gas in the saturation regime. To demonstrate it, a baseline-immune Lamb dip spectrum of the R1A2 transitions in the 2v2 + v3 band of methane was recorded. The line position was determined to be 6 076.108 457 7(11) cm-1, the relative uncertainty being 1.8 × 10-10.
The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, foll... more The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of the Consultative Committee for Units (CCU) on the redefinition of the kilogram, ampere, kelvin and mole. For the redefinition of the kelvin, the Boltzmann constant will be fixed with the numerical value 1.380 649 × 10 −23 J K −1. The relative standard uncertainty to be transferred to the thermodynamic temperature value of the triple point of water will be 3.7 × 10 −7 , corresponding to an uncertainty in temperature of 0.10 mK, sufficiently low for all practical purposes. With the redefinition of the kelvin, the broad research activities of the temperature community on the determination of the Boltzmann constant have been very successfully completed. In the following, a review of the determinations of the Boltzmann constant k, important for the new definition of the kelvin and performed in the last decade, is given.
New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas To cite this ... more New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas To cite this article: L Pitre et al 2017 Metrologia 54 856 View the article online for updates and enhancements.
... Precision spectroscopy of hydrogen and deuterium. MG Boshier * , PEG Baird * , CJ Foot * , EA... more ... Precision spectroscopy of hydrogen and deuterium. MG Boshier * , PEG Baird * , CJ Foot * , EA Hinds , MD Plimmer * , DN Stacey * , JB Swan , DA Tate § , DM Warrington & GK Woodgate *. ... To read this story in full you will need to login or make a payment (see right). ...
We have excited the 1S-2S transition in atomic hydrogen and deuterium by two-photon absorption of... more We have excited the 1S-2S transition in atomic hydrogen and deuterium by two-photon absorption of cw 243 nm light. The transition frequency has been measured by comparison with calibrated lines in the spectrum of the 130Te2 molecule, providing new precise values for the 1S Lamb shifts or the Rydberg constant.
Refractive index gas thermometry (RIGT) uses the dependence of the relative dielectric permittivi... more Refractive index gas thermometry (RIGT) uses the dependence of the relative dielectric permittivity on the density of a noble gas (He), typically measured with a temperature-controlled resonator. On an isotherm, to a good approximation, the slope of the dielectric permittivity versus pressure gives the thermodynamic temperature T. To measure T with a low uncertainty, one must measure the absolute value of the pressure with a low uncertainty and know the compressibility of the resonator wall. This article shows how to use RIGT in a novel way between 5 K and 25 K. Instead of changing the pressure on an isotherm (J.W. Schmidt et al., Phys. Rev. Lett., 98, 254504 (2007)), a constant pressure of pure helium gas is maintained at multiple temperatures. After calibration of the resonator under vacuum at different temperatures, all thermometry is performed at a single pressure and referred to a fixed point of the International Temperature Scale of 1990 (ITS-90) (here the neon triple point at 24.5561 K). The quantity that yields the temperature is the ratio of the resonance frequencies of a microwave mode in the resonator measured at the fixed point and at the unknown temperature. This paper describes the theoretical model of Single-Pressure Refractive Index Gas Thermometry (SPRIGT) and analyses the shifts and broadenings due to non-ideal behaviour. The technique should enable a helium-based measurement of thermodynamic temperature with a resolution better than 25 μK and an uncertainty of around 250 µK.
We have performed a new measurement of the Rydberg constant by frequency comparison of the 2S-8S ... more We have performed a new measurement of the Rydberg constant by frequency comparison of the 2S-8S and 2S-8D two-photon transitions in hydrogen with the difference of two optical standards connected to a frequency chain. Our result is: R∞=109 737.315 6830 (31) cm-1.
2004 Conference on Precision Electromagnetic Measurements, 2004
We have measured the frequency, isotope shift and hyperfine structure intervals of the 4d'05s 2S1... more We have measured the frequency, isotope shift and hyperfine structure intervals of the 4d'05s 2S12-+ 4d9 5S2 2D32 two-photon transition in 107Ag and 109Ag by laser spectroscopy of a thermal atomic beam. Frequencies were linked to the hyperfme component a3 of the line RI 11(18-1) in 12712 near 520 THz.
The Boltzmann constant k has been determined from a measurement of the speed of sound in helium g... more The Boltzmann constant k has been determined from a measurement of the speed of sound in helium gas in a quasi-spherical resonator (volume 0.5 l) maintained at a temperature close to the triple point of water (273.16 K). The acoustic velocity c is deduced from measured acoustic resonance frequencies and the dimensions of the quasi-sphere, the latter being obtained via simultaneous microwave resonance. Values of c are extrapolated to the zero pressure limit of ideal gas behaviour. We find J⋅K−1, a result consistent with previous measurements in our group and elsewhere. The value for k, which has a relative standard uncertainty of 1.02 ppm, lies 0.02 ppm below that of the CODATA 2010 adjustment.
Quantum and Semiclassical Optics: Journal of the European Optical Society Part B, 1998
ABSTRACT We describe an ongoing experiment to measure parity violation in atomic caesium, based o... more ABSTRACT We describe an ongoing experiment to measure parity violation in atomic caesium, based on detection by stimulated emission. Our goal is to measure to 1 a left-right asymmetry of to test electroweak theory and look for new physics beyond the Standard Model. The Cs highly forbidden transition, , is excited in a vapour (5-10 mtorr) by a pump laser pulse in a longitudinal electric field . The PV asymmetry resulting from the weak interaction during optical excitation is converted into an anisotropy in the gain of a probe laser pulse which stimulates the allowed transition , and manifests itself as a tiny -odd rotation of the probe's linear polarization. Differential polarimetry allows dark-field detection of the rotation angle with a baseline defined to better than and discrimination between true and pseudo-rotation. Lineshape-independent angle calibration is performed using a parity-conserving -even anisotropy. To isolate the parity-violating effect, we exploit the symmetry of revolution of the experiment by (i) rotating pump and probe linear polarizations around the beam axis and (ii) reversing in a cylindrically symmetric cell. After describing the apparatus and data acquisition procedure, we summarize the current experimental status and short-term prospects.
... 456483,198 1. [5] S. G uhdel , T. Badr, MD Plimmer, P. Juncar and ME Himbert, “Frequency meas... more ... 456483,198 1. [5] S. G uhdel , T. Badr, MD Plimmer, P. Juncar and ME Himbert, “Frequency measurement, isotope shift and hyperfine structure of the 4d9 5s' 2D5n + 4dl06p 2P3/2 transition in atomic silver ”, in Euro. Phvs. ... 59-68,1966. [7] U. Dinger, G. Eberz, G. Huber, R Menges ...
We outline progress towards the realisation of optical frequency standards based on narrow two-ph... more We outline progress towards the realisation of optical frequency standards based on narrow two-photon transitions in atomic silver. Subjects described include the detection of metastable atoms and the indirect determination of the 661.2 nm clock transition frequency.
The continuous expansion method is widely used by National metrology institutes for traceability ... more The continuous expansion method is widely used by National metrology institutes for traceability of vacuum measurements below 10 À3 Pa. It is usually implemented using a fixed conductance such as a small circular orifice. This article describes how LCM-LNE has used the method with a variable conductance and includes a detailed uncertainty budget.
The 1S–2S transition of atomic hydrogen has attracted considerable attention because of its extre... more The 1S–2S transition of atomic hydrogen has attracted considerable attention because of its extremely narrow natural width (1 Hz). High resolution Doppler-free spectra of this transition, obtainable by two-photon absorption, offer the prospect of precise tests of bound-state quantum electrodynamics (QED) and more accurate values for fundamental constants /1/. The two-photon absorption was first observed by HANSCH et al. /2/ at Stanford, in the first of a series of progressively more accurate measurements /3/. Their latest result is a measurement of the IS Lamb shift in hydrogen using continuous-wave radiation /4/.
Conference Digest Conference on Precision Electromagnetic Measurements
Summary form only given. We are developing an optical frequency standard based on the narrow 4d10... more Summary form only given. We are developing an optical frequency standard based on the narrow 4d10 5s 2S12/→4d9 5s2 2D52/ transition in atomic silver. We have realized a two-photon spectrometer and are now engaged in a measurement of the frequency of the broader but easier-to-detect two-photon transition to the 4d9 5s2 2D32/ level.
This paper shows how Angle-Resolved Scattering can reveal wear on engineered surfaces. The sample... more This paper shows how Angle-Resolved Scattering can reveal wear on engineered surfaces. The samples studied, three discs made of steel 100Cr6H used in gear wheels in the automotive industry, were assessed after they had undergone ball-on-disc tests. Scattering maps recorded for spatial frequencies from 0.1 mm À 1 to 2.7 mm À 1 show a contrast inversion around 0.36 mm À 1 revealing the wear trace. Besides measurements of rms roughness, where mean values are 20 nm and 24 nm depending on the locations considered, stationarity and isotropy, we demonstrate the ability of the technique to reveal localized wear on this type of surface in a rapid, robust and convenient way. We show that the tool trace is influenced by the load magnitude rather than by the number of oscillation cycles and highlight the key role played by surface roughness in how the sample responds to wear tests.
We have measured the Rydberg constant by frequency comparison of the three transitions 2S\/i-851/... more We have measured the Rydberg constant by frequency comparison of the three transitions 2S\/i-851/2, 2S1/2-8D3/2, and ISm-SDsn in hydrogen with the difference of two optical standards, the methane-stabilized He-Ne laser and the iodine-stabilized He-Ne laser. The frequency of the iodinestabilized He-Ne laser has been remeasured. The new value for the Rydberg constant, R™ = 109737.3156830(31) cm ~!, is currently the most precise available.
18th European Frequency and Time Forum (EFTF 2004), 2004
ABSTRACT We have measured the frequencies of the hyperfine components of the transition 4d10 5s 2... more ABSTRACT We have measured the frequencies of the hyperfine components of the transition 4d10 5s 2S1/2 → 4d9 5s22D3/2 in 107Ag and 109Ag, by Doppler-free two-photon laser spectroscopy of a thermal atomic beam and heterodyne calibration with respect to a molecular iodine line near 520 THz. We deduce the value 1 040 706 327 (3) MHz for the centre of gravity of a mixture of natural abundance. For the isotope shift, we obtain ν(109Ag)-ν(107Ag)=+599.6 (2) MHz. We find the magnetic hyperfine splitting constants of the excited state to be A(107Ag(2D3/2))=-315.9 (1) MHz and A(109Ag(2D3/2))=-363.3(1) MHz, an order of magnitude improvement over previous authors.
2018 Conference on Precision Electromagnetic Measurements (CPEM 2018), 2018
A novel single pressure refractive index gas thermometry(SPRIGT) allows the determination of ther... more A novel single pressure refractive index gas thermometry(SPRIGT) allows the determination of thermodynamic temperature of helium gas filled in quasi-spherical microwave cavity resonator(QMCR) by combination of microwave measurements, temperature and pressure control. A long-term temperature stability better than O.2mK is demanded for the QMCR from 5K to 24.5561 K. The uncertainty below 4ppm for pressure needs to precisely control the oscillation of temperature along the gas line. Microwave resonance frequency measurement in QMCR should be better than 2ppb. To meet these requirements, SPRIGT has been built in China and the first run experimental data was analysis in this paper.
In this article, we present an analysis of the stability of optical lattices. Starting with the s... more In this article, we present an analysis of the stability of optical lattices. Starting with the study of an unstable optical lattice, we establish a necessary and sufficient condition for intrinsic phase stability and discuss two practical solutions to fulfill this condition, namely, minimal and folded optical lattices. We then present a particular example of two-dimensional folded optical lattice, which has the advantages of being symmetric, possessing power recycling, and having a convenient geometry. We used this lattice for laser collimation of a continuous cesium beam in a fountain geometry.
We propose a new simple approximate solution to the two-state rate equation model for analyzing d... more We propose a new simple approximate solution to the two-state rate equation model for analyzing decay signals of saturation cavity ring-down spectrometry in the adiabatic and low-saturation regime. It helps obtain baseline-immune Doppler-free spectra for hyperfine transitions and linear absorption coefficients of a gas in the saturation regime. To demonstrate it, a baseline-immune Lamb dip spectrum of the R1A2 transitions in the 2v2 + v3 band of methane was recorded. The line position was determined to be 6 076.108 457 7(11) cm-1, the relative uncertainty being 1.8 × 10-10.
The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, foll... more The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of the Consultative Committee for Units (CCU) on the redefinition of the kilogram, ampere, kelvin and mole. For the redefinition of the kelvin, the Boltzmann constant will be fixed with the numerical value 1.380 649 × 10 −23 J K −1. The relative standard uncertainty to be transferred to the thermodynamic temperature value of the triple point of water will be 3.7 × 10 −7 , corresponding to an uncertainty in temperature of 0.10 mK, sufficiently low for all practical purposes. With the redefinition of the kelvin, the broad research activities of the temperature community on the determination of the Boltzmann constant have been very successfully completed. In the following, a review of the determinations of the Boltzmann constant k, important for the new definition of the kelvin and performed in the last decade, is given.
New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas To cite this ... more New measurement of the Boltzmann constant k by acoustic thermometry of helium-4 gas To cite this article: L Pitre et al 2017 Metrologia 54 856 View the article online for updates and enhancements.
... Precision spectroscopy of hydrogen and deuterium. MG Boshier * , PEG Baird * , CJ Foot * , EA... more ... Precision spectroscopy of hydrogen and deuterium. MG Boshier * , PEG Baird * , CJ Foot * , EA Hinds , MD Plimmer * , DN Stacey * , JB Swan , DA Tate § , DM Warrington & GK Woodgate *. ... To read this story in full you will need to login or make a payment (see right). ...
We have excited the 1S-2S transition in atomic hydrogen and deuterium by two-photon absorption of... more We have excited the 1S-2S transition in atomic hydrogen and deuterium by two-photon absorption of cw 243 nm light. The transition frequency has been measured by comparison with calibrated lines in the spectrum of the 130Te2 molecule, providing new precise values for the 1S Lamb shifts or the Rydberg constant.
Refractive index gas thermometry (RIGT) uses the dependence of the relative dielectric permittivi... more Refractive index gas thermometry (RIGT) uses the dependence of the relative dielectric permittivity on the density of a noble gas (He), typically measured with a temperature-controlled resonator. On an isotherm, to a good approximation, the slope of the dielectric permittivity versus pressure gives the thermodynamic temperature T. To measure T with a low uncertainty, one must measure the absolute value of the pressure with a low uncertainty and know the compressibility of the resonator wall. This article shows how to use RIGT in a novel way between 5 K and 25 K. Instead of changing the pressure on an isotherm (J.W. Schmidt et al., Phys. Rev. Lett., 98, 254504 (2007)), a constant pressure of pure helium gas is maintained at multiple temperatures. After calibration of the resonator under vacuum at different temperatures, all thermometry is performed at a single pressure and referred to a fixed point of the International Temperature Scale of 1990 (ITS-90) (here the neon triple point at 24.5561 K). The quantity that yields the temperature is the ratio of the resonance frequencies of a microwave mode in the resonator measured at the fixed point and at the unknown temperature. This paper describes the theoretical model of Single-Pressure Refractive Index Gas Thermometry (SPRIGT) and analyses the shifts and broadenings due to non-ideal behaviour. The technique should enable a helium-based measurement of thermodynamic temperature with a resolution better than 25 μK and an uncertainty of around 250 µK.
We have performed a new measurement of the Rydberg constant by frequency comparison of the 2S-8S ... more We have performed a new measurement of the Rydberg constant by frequency comparison of the 2S-8S and 2S-8D two-photon transitions in hydrogen with the difference of two optical standards connected to a frequency chain. Our result is: R∞=109 737.315 6830 (31) cm-1.
2004 Conference on Precision Electromagnetic Measurements, 2004
We have measured the frequency, isotope shift and hyperfine structure intervals of the 4d'05s 2S1... more We have measured the frequency, isotope shift and hyperfine structure intervals of the 4d'05s 2S12-+ 4d9 5S2 2D32 two-photon transition in 107Ag and 109Ag by laser spectroscopy of a thermal atomic beam. Frequencies were linked to the hyperfme component a3 of the line RI 11(18-1) in 12712 near 520 THz.
The Boltzmann constant k has been determined from a measurement of the speed of sound in helium g... more The Boltzmann constant k has been determined from a measurement of the speed of sound in helium gas in a quasi-spherical resonator (volume 0.5 l) maintained at a temperature close to the triple point of water (273.16 K). The acoustic velocity c is deduced from measured acoustic resonance frequencies and the dimensions of the quasi-sphere, the latter being obtained via simultaneous microwave resonance. Values of c are extrapolated to the zero pressure limit of ideal gas behaviour. We find J⋅K−1, a result consistent with previous measurements in our group and elsewhere. The value for k, which has a relative standard uncertainty of 1.02 ppm, lies 0.02 ppm below that of the CODATA 2010 adjustment.
Quantum and Semiclassical Optics: Journal of the European Optical Society Part B, 1998
ABSTRACT We describe an ongoing experiment to measure parity violation in atomic caesium, based o... more ABSTRACT We describe an ongoing experiment to measure parity violation in atomic caesium, based on detection by stimulated emission. Our goal is to measure to 1 a left-right asymmetry of to test electroweak theory and look for new physics beyond the Standard Model. The Cs highly forbidden transition, , is excited in a vapour (5-10 mtorr) by a pump laser pulse in a longitudinal electric field . The PV asymmetry resulting from the weak interaction during optical excitation is converted into an anisotropy in the gain of a probe laser pulse which stimulates the allowed transition , and manifests itself as a tiny -odd rotation of the probe's linear polarization. Differential polarimetry allows dark-field detection of the rotation angle with a baseline defined to better than and discrimination between true and pseudo-rotation. Lineshape-independent angle calibration is performed using a parity-conserving -even anisotropy. To isolate the parity-violating effect, we exploit the symmetry of revolution of the experiment by (i) rotating pump and probe linear polarizations around the beam axis and (ii) reversing in a cylindrically symmetric cell. After describing the apparatus and data acquisition procedure, we summarize the current experimental status and short-term prospects.
... 456483,198 1. [5] S. G uhdel , T. Badr, MD Plimmer, P. Juncar and ME Himbert, “Frequency meas... more ... 456483,198 1. [5] S. G uhdel , T. Badr, MD Plimmer, P. Juncar and ME Himbert, “Frequency measurement, isotope shift and hyperfine structure of the 4d9 5s' 2D5n + 4dl06p 2P3/2 transition in atomic silver ”, in Euro. Phvs. ... 59-68,1966. [7] U. Dinger, G. Eberz, G. Huber, R Menges ...
We outline progress towards the realisation of optical frequency standards based on narrow two-ph... more We outline progress towards the realisation of optical frequency standards based on narrow two-photon transitions in atomic silver. Subjects described include the detection of metastable atoms and the indirect determination of the 661.2 nm clock transition frequency.
The continuous expansion method is widely used by National metrology institutes for traceability ... more The continuous expansion method is widely used by National metrology institutes for traceability of vacuum measurements below 10 À3 Pa. It is usually implemented using a fixed conductance such as a small circular orifice. This article describes how LCM-LNE has used the method with a variable conductance and includes a detailed uncertainty budget.
The 1S–2S transition of atomic hydrogen has attracted considerable attention because of its extre... more The 1S–2S transition of atomic hydrogen has attracted considerable attention because of its extremely narrow natural width (1 Hz). High resolution Doppler-free spectra of this transition, obtainable by two-photon absorption, offer the prospect of precise tests of bound-state quantum electrodynamics (QED) and more accurate values for fundamental constants /1/. The two-photon absorption was first observed by HANSCH et al. /2/ at Stanford, in the first of a series of progressively more accurate measurements /3/. Their latest result is a measurement of the IS Lamb shift in hydrogen using continuous-wave radiation /4/.
Conference Digest Conference on Precision Electromagnetic Measurements
Summary form only given. We are developing an optical frequency standard based on the narrow 4d10... more Summary form only given. We are developing an optical frequency standard based on the narrow 4d10 5s 2S12/→4d9 5s2 2D52/ transition in atomic silver. We have realized a two-photon spectrometer and are now engaged in a measurement of the frequency of the broader but easier-to-detect two-photon transition to the 4d9 5s2 2D32/ level.
This paper shows how Angle-Resolved Scattering can reveal wear on engineered surfaces. The sample... more This paper shows how Angle-Resolved Scattering can reveal wear on engineered surfaces. The samples studied, three discs made of steel 100Cr6H used in gear wheels in the automotive industry, were assessed after they had undergone ball-on-disc tests. Scattering maps recorded for spatial frequencies from 0.1 mm À 1 to 2.7 mm À 1 show a contrast inversion around 0.36 mm À 1 revealing the wear trace. Besides measurements of rms roughness, where mean values are 20 nm and 24 nm depending on the locations considered, stationarity and isotropy, we demonstrate the ability of the technique to reveal localized wear on this type of surface in a rapid, robust and convenient way. We show that the tool trace is influenced by the load magnitude rather than by the number of oscillation cycles and highlight the key role played by surface roughness in how the sample responds to wear tests.
We have measured the Rydberg constant by frequency comparison of the three transitions 2S\/i-851/... more We have measured the Rydberg constant by frequency comparison of the three transitions 2S\/i-851/2, 2S1/2-8D3/2, and ISm-SDsn in hydrogen with the difference of two optical standards, the methane-stabilized He-Ne laser and the iodine-stabilized He-Ne laser. The frequency of the iodinestabilized He-Ne laser has been remeasured. The new value for the Rydberg constant, R™ = 109737.3156830(31) cm ~!, is currently the most precise available.
18th European Frequency and Time Forum (EFTF 2004), 2004
ABSTRACT We have measured the frequencies of the hyperfine components of the transition 4d10 5s 2... more ABSTRACT We have measured the frequencies of the hyperfine components of the transition 4d10 5s 2S1/2 → 4d9 5s22D3/2 in 107Ag and 109Ag, by Doppler-free two-photon laser spectroscopy of a thermal atomic beam and heterodyne calibration with respect to a molecular iodine line near 520 THz. We deduce the value 1 040 706 327 (3) MHz for the centre of gravity of a mixture of natural abundance. For the isotope shift, we obtain ν(109Ag)-ν(107Ag)=+599.6 (2) MHz. We find the magnetic hyperfine splitting constants of the excited state to be A(107Ag(2D3/2))=-315.9 (1) MHz and A(109Ag(2D3/2))=-363.3(1) MHz, an order of magnitude improvement over previous authors.
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Papers by Mark D Plimmer