Spectral purity and long-term stability of CO/sub 2/ lasers at the Hertz level

Bernard, Vladan; Durand, Pierre-Emmanuel; George, T.; Nicolaisen, H.‐W.; Amy‐Klein, Anne; Chardonnet, Ch.

doi:10.1109/3.469270

Cited by 14 publications

(12 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Very recently this difficulty has been overcome by French chemists. Such an experiment can now be tried with a real chance of success thanks to the spectacular progress accomplished in the control of CO 2 lasers (Bernard et al 1995). The measurements will use a CO 2 laser stabilized to 0.1 Hz on 100 s and will compare the vibration frequencies of the two enantiomers placed in identical chambers (Chardonnet and Bordé, private communication).…”

Section: An Experimental Project To Search For An Energy Difference Bmentioning

confidence: 99%

Parity violation in atoms

1997

View full text Add to dashboard Cite

Optical experiments have demonstrated cases in which mirror symmetry in stable atoms is broken during the absorption or emission of light. Such results, which are in conflict with quantum electrodynamics, support the theory of unification of the electromagnetic and weak interactions. The interpretation of the experimental results is based on exchanges of weak neutral Z 0 bosons between the electrons and the nucleus of the atom. A concise review of these phenomena in atomic physics is presented. The role of precise caesium parity-violation experiments, as a source of valuable information about electroweak physics, is illustrated by examples pertaining to experimental conditions which, in some cases, are not accessible to accelerator experiments. We give the basic principles of experiments, some under way and others completed, where a quantitative determination of the nuclear weak charge, Q W , which plays for the Z 0 exchange the same role as the electric charge for the Coulomb interaction is to be, or has been achieved. In the most recent and most precise experiment the accuracy on Q W is limited to 1% by the uncertainty due to atomic physics calculations. Such a result challenges specialists in atomic theory and nuclear structure, since a more accurate determination of Q W would mean more stringent constraints upon possible extensions of the standard model. Moreover, clear evidence has recently been obtained for the existence of the nuclear anapole moment, which describes the valence electron interaction with a chiral nuclear-magnetization component induced by the parity-violating nuclear forces. In writing this review, our hope was to make clear that any improvement in atomic parity-violation measurements will allow the exploration of new areas of electroweak physics.

show abstract

Section: An Experimental Project To Search For An Energy Difference Bmentioning

confidence: 99%

Parity violation in atoms

1997

View full text Add to dashboard Cite

show abstract

“…In this Section we focus on CO 2 lasers which are commonly used for high-resolution rovibrational spectroscopy between 9 and 11 µm, and details the developments made at LPL over the past years of high resolution spectrometers based on stabilized CO 2 lasers. Lasers filled with the most abundant isotopic species 12 26 . They show a frequency drift of a few Hz/s.…”

Section: Laser Frequency Controlmentioning

confidence: 99%

“…They show a frequency drift of a few Hz/s. From the beat-note signal between two identical lasers, we deduced a free-running laser line width of about 1 kHz 26 . This makes possible rovibrational spectroscopy at a resolution of ~3 10 -8 .…”

Section: Laser Frequency Controlmentioning

confidence: 99%

“…To simultaneously enhance the short-term stability and the line width, the molecular line is detected in transmission of a Fabry-Perot cavity. In doing so, the signal-to-noise ratio increases proportionally to the cavity finesse, enabling a better frequency noise rejection 26,28 . Several molecules can be used for the CO 2 laser stabilization, among which CO 2 29,30 itself.…”

Section: Laser Frequency Controlmentioning

confidence: 99%

See 1 more Smart Citation

Probing weak force-induced parity violation by high-resolution mid-infrared molecular spectroscopy

et al. 2013

Self Cite

View full text Add to dashboard Cite

To date no experiment has reached the level of sensitivity required to observe weak nuclear force induced parity violation (PV) energy differences in chiral molecules. In this paper, we present the approach, adopted at Laboratoire de Physique des Lasers (LPL), to measure frequency differences in the vibrational spectrum of enantiomers. We review different spectroscopic methods developed at LPL leading to the highest resolutions, as well as 20 years of CO 2 laser stabilization work enabling such precise measurements. After a first attempt to observe PV vibrational frequency shifts using sub-Doppler saturated absorption spectroscopy in a cell, we are currently aiming at an experiment based on Doppler-free two-photon Ramsey interferometry on a supersonic beam. We report on our latest progress towards observing PV with chiral organo-metallic complexes containing a heavy rhenium atom.

show abstract

“…However, molecular degrees of freedom cannot be controlled as efficiently as atomic ones, leading to limited frequency reproducibility and accuracy. Alternatively, several attempts to develop MIR US cavities have been made, but the performance is far from what is reported in the near-infrared (NIR) or visible spectral regions 25,26 .…”

mentioning

confidence: 99%

Quantum cascade laser frequency stabilization at the sub-Hz level

et al. 2015

View full text Add to dashboard Cite

High-precision measurements with molecules may refine our knowledge of various fields of physics, from atmospheric and interstellar physics to the standard model or physics beyond it. Most of them can be cast as absorption frequency measurements, particularly in the mid-infrared 'molecular fingerprint' region, creating the need for narrow-linewidth lasers of well-controlled frequency. Quantum cascade lasers provide a wide spectral coverage anywhere in the mid-infrared, but show substantial free-running frequency fluctuations. Here, we demonstrate that the excellent stability and accuracy of an ultra-stable near-infrared laser, transferred from a metrological institute through a fibre link, can be copied to a quantum cascade laser using an optical frequency comb. The obtained relative stability and accuracy of 2 × 10 −15 and 10 −14 exceed those demonstrated so far with quantum cascade lasers by almost two orders of magnitude. This set-up enables us to measure molecular absorption frequencies with state-of-the-art uncertainties, confirming its potential for ultra-highprecision spectroscopy.M olecules are increasingly being used in precision tests of physics thanks to progress made in controlling molecular degrees of freedom 1,2 . They are now being used, for example, to test fundamental symmetries 3-5 and to measure fundamental constants 6-8 and their possible variation in time 9-11 . Most of these experiments are spectroscopic precision measurements and are often in the mid-infrared (MIR) domain where the molecules exhibit intense and narrow rovibrational transitions. This creates a need for efficient MIR laser sources, prompting efforts to develop ultra-stable and accurate continuous wave (c.w.) lasers as well as MIR frequency combs (refs 12 and 13 for instance). Quantum cascade lasers 14,15 (QCLs) are promising c.w. sources-they are available anywhere in the 3-25 µm MIR range, and each QCL can be tuned over several hundreds of gigahertz. However, their freerunning linewidth of tens to thousands of kilohertz makes their frequency stabilization challenging [16][17][18][19][20][21][22][23][24][25] .Common references used for frequency stabilization in the MIR region include molecular rovibrational absorption lines 3,26 . However, molecular degrees of freedom cannot be controlled as efficiently as atomic ones, leading to limited frequency reproducibility and accuracy. Attempts to develop MIR ultra-stable cavities have been made, but their performances are far from those reported in the near-infrared (NIR) or visible regions 27,28 . It is thus appealing to use the best ultra-stable lasers as frequency references. As these are predominantly in the NIR region, it is necessary to bridge the gap between the NIR and MIR domains. This is possible using an optical frequency comb (OFC). The MIR frequency is locked to a high harmonic of the OFC repetition rate using sum-or difference-frequency generation processes. This not only provides ultimate stabilities of lasers locked to state-of-the-art ultra-stable cavities 29 , but ...

show abstract

Spectral purity and long-term stability of CO/sub 2/ lasers at the Hertz level

Cited by 14 publications

References 8 publications

Parity violation in atoms

Parity violation in atoms

Probing weak force-induced parity violation by high-resolution mid-infrared molecular spectroscopy

Quantum cascade laser frequency stabilization at the sub-Hz level

Contact Info

Product

Resources

About