This paper gives the 2010 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. The 2010 adjustment takes into account the data considered in the 2006 adjustment as well as the data that became available from 1 January 2007, after the closing date of that adjustment, until 31 December 2010, the closing date of the new adjustment. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2010 set replaces the previously recommended 2006 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.

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CODATA Recommended Values of the Fundamental Physical Constants: 2006

Dual-comb spectroscopy is an emerging new spectroscopic tool that exploits the frequency resolution, frequency accuracy, broad bandwidth, and brightness of frequency combs for ultrahigh-resolution, high-sensitivity broadband spectroscopy. By using two coherent frequency combs, dual-comb spectroscopy allows a sample’s spectral response to be measured on a comb tooth-by-tooth basis rapidly and without the size constraints or instrument response limitations of conventional spectrometers. This review describes dual-comb spectroscopy and summarizes the current state of the art. As frequency comb technology progresses, dual-comb spectroscopy will continue to mature and could surpass conventional broadband spectroscopy for a wide range of laboratory and field applications.

Dual-comb spectroscopy

We report on the Bose-Einstein condensation of more than 10(5) Li2 molecules in an optical trap starting from a spin mixture of fermionic lithium atoms During forced evaporative cooling, the molecules are formed by three-body recombination near a Feshbach resonance and finally condense in a long-lived thermal equilibrium state We measured the characteristic frequency of a collective excitation mode and demonstrated the magnetic field-dependent mean field by controlled condensate spilling

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Bose-Einstein condensation of molecules

Ultrahigh-Q optical resonators are being studied across a wide range of fields, including quantum information, nonlinear optics, cavity optomechanics and telecommunications. Here, we demonstrate a new resonator with a record Q-factor of 875 million for on-chip devices. The fabrication of our device avoids the requirement for a specialized processing step, which in microtoroid resonators8 has made it difficult to control their size and achieve millimetre- and centimetre-scale diameters. Attaining these sizes is important in applications such as microcombs and potentially also in rotation sensing. As an application of size control, stimulated Brillouin lasers incorporating our device are demonstrated. The resonators not only set a new benchmark for the Q-factor on a chip, but also provide, for the first time, full compatibility of this important device class with conventional semiconductor processing. This feature will greatly expand the range of possible ‘system on a chip’ functions enabled by ultrahigh-Q devices.

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Chemically etched ultrahigh-Q wedge-resonator on a silicon chip

In atomic laser cooling, preparation of the motional quantum ground state has been achieved using resolved-sideband cooling of trapped ions. Here, we report the first demonstration of resolved-sideband cooling of a mesoscopic mechanical oscillator, a key step towards ground-state cooling as quantum back-action is sufficiently suppressed in this scheme. A laser drives the first lower sideband of an optical microcavity resonance, the decay rate of which is twenty times smaller than the eigenfrequency of the associated mechanical oscillator. Cooling rates above 1.5 MHz are attained, three orders of magnitude higher than the intrinsic dissipation rate of the mechanical device that is independently monitored at the level. Direct spectroscopy of the motional sidebands of the cooling laser confirms the expected suppression of motional increasing processes during cooling. Moreover, using two-mode pumping, this regime could enable motion measurement beyond the standard quantum limit and the concomitant generation of non-classical states of motion. Laser-driven resolved sideband cooling of the resonant vibrational mode of a toroidal microcavity represents another step towards reaching the quantum ground state.

Resolved Sideband Cooling of a Micromechanical Oscillator

Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity

We have determined the 1S Lamb shift in atomic hydrogen with a precision of 2 parts in 10/sup 4/ by measuring the frequency of the 1S-2S transition observed by continuous-wave Doppler-free two-photon spectroscopy. We employ an interferometrically calibrated absorption line in /sup 130/Te/sub 2/ as our reference and obtain a 1S-2S interval of 2 466 061 413.8(1.5) MHz. Choosing a value of the Rydberg constant measured independently by high-resolution spectroscopy of the hydrogen Balmer-..beta.. transition, we find the 1S Lamb shift to be 8173.3(1.7) MHz, in good agreement with the theoretical value of 8172.94(9) MHz.

Continuous-wave measurement of the 1S Lamb shift in atomic hydrogen.

We have observed the $1S\ensuremath{-}2S$ transition in atomic hydrogen gas with a resolution of 5 parts in ${10}^{9}$ by Doppler-free two-photon spectroscopy, using multimilliwatt cw radiation near 243 nm generated by sum-frequency mixing. The experiment opens the way to substantial increases in the accuracy of the Rydberg constant, the electron/proton mass ratio, and the Lamb shift of the hydrogen $1S$ ground state.

Continuous-wave two-photon spectroscopy of the 1S-2S transition in hydrogen.

We have measured the 1S-2S transition frequency in atomic hydrogen with a precision of 7 parts in 10/sup 10/ by continuous-wave Doppler-free two-photon spectroscopy. We employ cavity-enhanced multimilliwatt radiation near 243 nm produced by sum-frequency generation, and we observe the 1S-2S transition in a low-pressure hydrogen-helium cell with a resolution of 3 parts in 10/sup 9/. For a frequency comparison we detect an optical heterodyne signal at the difference frequency between the 243-nm light used to excite the 1S-2S transition and the second harmonic of a reference laser locked to an interferometrically calibrated /sup 130/Te/sub 2/ absorption line near 486 nm. After determining systematic corrections due to the pressure shift of the F = 1 hyperfine component in a 0.7 vol. % hydrogen--99.3 vol. % helium gaseous mixture, we obtain the energy-level separation f(1S-2S) = 2 466 061 413.2(18) MHz. Choosing a value of the Rydberg constant measured independently by high-resolution spectroscopy of the hydrogen Balmer-..beta.. transition, we find the hydrogen ground-state Lamb shift to be f/sub LS/(1S) = 8173.9(19) MHz, in good agreement with the theoretical value of 8172.89(9) MHz.

B. Couillaud

Papers

Laser frequency stabilization by polarization spectroscopy of a reflecting reference cavity

Continuous-wave measurement of the 1S Lamb shift in atomic hydrogen.

Continuous-wave two-photon spectroscopy of the 1S-2S transition in hydrogen.

Continuous-wave measurement of the hydrogen 1S-2S transition frequency

Doppler-free spectroscopy in a hollow-cathode discharge: Isotope-shift measurements in molybdenum