scholarly journals HIGH-PRECISION MID-IR MOLECULAR SPECTROSCOPY WITH TRACEABILITY TO PRIMARY FREQUENCY STANDARDS USING SUB-Hz FREQUENCY COMB-STABILIZED QCLS

2018 ◽  
Author(s):  
Benoit Darquie ◽  
Anne Amy-Klein ◽  
Paul-Eric Pottie ◽  
Dan Xu ◽  
Won-Kyu Lee ◽  
...  
Keyword(s):  
High Precision ◽  
Molecular Spectroscopy ◽  
Frequency Comb ◽  
Frequency Standards ◽  
Primary Frequency

scholarly journals Broadband high-resolution molecular spectroscopy with interleaved mid-infrared frequency combs

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. V. Muraviev ◽  
D. Konnov ◽  
K. L. Vodopyanov
Keyword(s):  
High Resolution ◽  
Molecular Spectroscopy ◽  
Frequency Comb ◽  
Acquisition Time ◽  
Sampling Point ◽  
Dual Frequency ◽  
Mid Infrared ◽  
Frequency Combs ◽  
Spectral Bands ◽  
Primary Frequency

Abstract Traditionally, there has been a trade-off in spectroscopic measurements between high resolution, broadband coverage, and acquisition time. Originally envisioned for precision spectroscopy of the hydrogen atom in the ultraviolet, optical frequency combs are now commonly used for probing molecular ro-vibrational transitions throughout broad spectral bands in the mid-infrared providing superior resolution, speed, and the capability of referencing to the primary frequency standards. Here we demonstrate the acquisition of 2.5 million spectral data points over the continuous wavelength range of 3.17–5.13 µm (frequency span 1200 cm−1, sampling point spacing 13–21 MHz), via interleaving comb-tooth-resolved spectra acquired with a highly-coherent broadband dual-frequency-comb system based on optical subharmonic generation. With the original comb-line spacing of 115 MHz, overlaying eight spectra with gradually shifted comb lines we fully resolve the amplitude and phase spectra of molecules with narrow Doppler lines, such as carbon disulfide (CS2) and its three isotopologues.

Mid-infrared frequency comb for broadband high precision and sensitivity molecular spectroscopy

2014 ◽  
Vol 39 (17) ◽  
pp. 5050 ◽  
Author(s):  
I. Galli ◽  
S. Bartalini ◽  
P. Cancio ◽  
F. Cappelli ◽  
G. Giusfredi ◽  
...  
Keyword(s):  
High Precision ◽  
Molecular Spectroscopy ◽  
Frequency Comb ◽  
Mid Infrared

scholarly journals Direct Observation of Terahertz Frequency Comb Generation in Difference-Frequency Quantum Cascade Lasers

2021 ◽  
Vol 11 (4) ◽  
pp. 1416
Author(s):  
Luigi Consolino ◽  
Malik Nafa ◽  
Michele De Regis ◽  
Francesco Cappelli ◽  
Saverio Bartalini ◽  
...  
Keyword(s):  
Near Infrared ◽  
Quantum Cascade Lasers ◽  
Molecular Spectroscopy ◽  
Frequency Comb ◽  
Frequency Standard ◽  
Difference Frequency ◽  
Heterodyne Detection ◽  
Optical Rectification ◽  
Total Output ◽  
Quantum Cascade

Terahertz quantum cascade laser sources based on intra-cavity difference frequency generation from mid-IR devices are an important asset for applications in rotational molecular spectroscopy and sensing, being the only electrically pumped device able to operate in the 0.6–6 THz range without the need of bulky and expensive liquid helium cooling. Here we present comb operation obtained by intra-cavity mixing of a distributed feedback laser at λ = 6.5 μm and a Fabry–Pérot device at around λ = 6.9 μm. The resulting ultra-broadband THz emission extends from 1.8 to 3.3 THz, with a total output power of 8 μW at 78 K. The THz emission has been characterized by multi-heterodyne detection with a primary frequency standard referenced THz comb, obtained by optical rectification of near infrared pulses. The down-converted beatnotes, simultaneously acquired, confirm an equally spaced THz emission down to 1 MHz accuracy. In the future, this setup can be used for Fourier transform based evaluation of the phase relation among the emitted THz modes, paving the way to room-temperature, compact, and field-deployable metrological grade THz frequency combs.

OPTICAL CLOCKS AND FREQUENCY METROLOGY FOR SPACE

2007 ◽  
Vol 16 (12b) ◽  
pp. 2537-2540
Author(s):  
HUGH KLEIN
Keyword(s):  
European Space Agency ◽  
Frequency Standard ◽  
Optical Frequency ◽  
Fundamental Physics ◽  
Frequency Standards ◽  
Space Agency ◽  
Primary Frequency ◽  
Measurement Capabilities ◽  
Science Activities ◽  
Frequency Metrology

Optical frequency standards and femtosecond comb measurement capabilities now rival and in some cases exceed those of microwave devices, with further improvements anticipated. Opportunities are emerging for the application of highly stable and accurate optical frequency devices to fundamental physics space science activities, and the European Space Agency (ESA) has recently commissioned studies on different aspects of optical clocks in space. This paper highlights some examples, including the difficulty of comparing very accurate terrestrial clocks at different locations due to fluctuations of the geoid; by locating a primary frequency standard in space, one could avoid geoid-related gravitational redshifts.

Accuracy Evaluation and Stability of the NBS Primary Frequency Standards

1974 ◽  
Vol 23 (4) ◽  
pp. 489-501 ◽  
Author(s):  
David J. Glaze ◽  
Helmut Hellwig ◽  
David W. Allan ◽  
Stephen Jarvis ◽  
Arthur E. Wainwright
Keyword(s):  
Accuracy Evaluation ◽  
Frequency Standards ◽  
Primary Frequency

High-Precision Measurement of Terahertz Frequency Based on Frequency Comb

2016 ◽  
Vol 36 (4) ◽  
pp. 0412002 ◽  
Author(s):  
孙青 Sun Qing ◽  
杨奕 Yang Yi ◽  
孟飞 Meng Fei ◽  
邓玉强 Deng Yuqiang
Keyword(s):  
High Precision ◽  
Precision Measurement ◽  
Frequency Comb ◽  
Terahertz Frequency ◽  
High Precision Measurement

scholarly journals Progress in Realization of the Time Unit and Scales

1995 ◽  
Vol 10 ◽  
pp. 253-254
Author(s):  
J. Kovalevsky
Keyword(s):  
Universal Time ◽  
Atomic Scale ◽  
Frequency Standards ◽  
Unit Scale ◽  
Combining Data ◽  
Great Progress ◽  
Scale Interval ◽  
To Come ◽  
Primary Frequency ◽  
Atomic Time

AbstractThe establishment of the TAI is done in two steps: the construction of the EAT from clocks in laboratories, then its steering by primary frequency standards. Great progress in the precision and stability of EAL was made by the generalized use of GPS time transfer and by the introduction of hydrogen masers and new very performant clocks. Only two primary frequency standards are sufficiently accurate to steer the frequency of TAI, but new standards are now being assessed. The present stability of TAI is 5.10−15 and the accuracy 2.10−14. Improvements should occur in the years to come.The establishment of the International Atomic Time (TAI) and the resulting Coordinated Universal Time (UTC) by the time section of BIPM is done in two steps (Guinot and Thomas, 1988). At first, a free atomic scale, EAL (Echelle atomique libre) is built in two month blocks combining data from about 200 atomic clocks kept by 60 laboratories and regularly reported to the BIPM by 45 centres which maintain a local coordinated universal time, UTC(k). Then, the duration of the scale interval of EAL is compared with data from primary caesium standards producing the SI second which, in turn, is converted on the rotating geoid as the unit scale of TAL A linear function of time with the necessary slope is added to EAL to ensure the accuracy of the TAI scale interval.

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