Buffer gas induced collision shift for the 88^{88}Sr 1S0−3P1\bf{^1S_0-^3P_1} clock transition

Precision saturation spectroscopy of the $^{88}{\rm Sr} ^1S_0-^3P_1$ is performed in a vapor cell filled with various rare gas including He, Ne, Ar, and Xe. By continuously calibrating the absolute frequency of the probe laser, buffer gas induced collision shifts of $\sim$kHz are detected with gas pressure of 1-20 mTorr. Helium gave the largest fractional shift of $1.6 \times 10^{-9} {\rm Torr}^{-1}$. Comparing with a simple impact calculation and a Doppler-limited experiment of Holtgrave and Wolf [Phys. Rev. A {\bf 72}, 012711 (2005)], our results show larger broadening and smaller shifting coefficient, indicating effective atomic loss due to velocity changing collisions. The applicability of the result to the $^1S_0-^3P_0$ optical lattice clock transition is also discussed

Application of Cavity-Enhanced Comb-Based FourierTransformSpectroscopy to Line Shape Study of CarbonMonoxide in Argon

We performed measurements of overtone band of CO using cavity-enhanced Fourier-transform spectrometer with sub-nominal resolution. The system’s performance allows to study collisional effects not described by the Voigt profile and precise determination of line parameters

Line Shape Measurements of CO Using Frequency Comb Based Cavity-Enhanced Absorption Spectroscopy

We performed measurements of overtone band of CO using a frequency comb based cavity-enhanced absorption spectroscopy and Fourier-transform spectrometer with sub-nominal resolution. The technique allows to measure and determine precisely line-shape parameters in wide range

Spectral line shapes of P-branch transitions of oxygen B-band

<p>The precise line-shape measurements of self- and foreign-broadened P-branch transitions of the oxygen B band near 689 nm are presented. Data were obtained using the Pound–Drever–Hall-locked frequency-stabilized cavity ring-down spectrometer assisted by the optical frequency comb.^1,2 This technique enables us to achieve high spectral resolution (about 1 MHz) and high signal-to-noise ratio spectra (above 10000:1) of weak transitions.^3,4 It is showed that the inclusion of the line-narrowing effects (Dicke narrowing or the speed dependence of collisional broadening) is necessary to properly model measured line shapes. The multispectrum fitting technique is used to minimize correlation between line-shape parameters. Relations between the line narrowing obtained from different line-shape models in the low pressure limit (below 5 kPa) were verified experimentally. Line positions with uncertainties of about 170 kHz, intensities and the collisional broadening coefficients with uncertainties of about 0.5% are reported and compared to data available in the literature.⁵</p> <p>The research is part of the program of the National Laboratory FAMO in Toruń, Poland, and is supported by the Polish National Science Centre Projects no. DEC-2011/01/B/ST2/00491 and UMO-2012/05/N/ST2/02717. The research is also supported by the Foundation for Polish Science TEAM and HOMING PLUS Projects co-financed by the EU European Regional Development Fund. A. Cygan is partially supported by the Foundation for Polish Science START Project.</p