Spectral line narrowing in a gas by atoms trapped in a standing light wave

Yoav Sagi, Ido Almog, Nir Davidson

Victor Yu. Argonov

The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field may suppress packet splitting for some atoms having specific velocities in a narrow range. These atoms remain localized in a small space for a long time. We propose that in a real experiment with cold atomic gas this effect may decrease the velocity distribution of atoms (the field traps the atoms with such specific velocities while all other atoms leave the field)

Wim Ubachs, Frank M. J. Cozijn, Meissa L. Diouf +3 more

In the early days of laser spectroscopy, Letokhov and Chebotayev proposed a scheme for measuring narrow spectral lines where the resolution is not restricted to Doppler effects because the molecules are entrained in a standing-wave light field. Now, such one-dimensional trapping in the intensity maxima of an intracavity field, slightly detuned from resonance, is experimentally demonstrated in the measurement of the very weak S(0) (2-0) quadrupole overtone transition in H_{2} at 1189 nm. The trapping manifests as an extremely narrow absorption feature at the predicted zero-recoil position, a 70 kHz shift from the blue-recoil component observed in Lamb-dip spectroscopy. A quantitative analysis of the saturation and trapping conditions supports the findings.

Bindiya Arora, Marianna S. Safronova, Charles W. Clark

Shuyu Zhou, Chen Chen, Bowen Xu +3 more

We propose a method to characterize the ultra-narrow momentum distribution of atomic gases by employing a standing-wave light-pulse sequences beam splitter. The mechanism of beam splitting is analyzed in detail, and the influence of a finite-width momentum distribution on the population of each diffraction order is given. The temperature of ultracold atomic gases can be calibrated by measuring the ratio of population in different diffraction orders after double standing-wave light pulses. We obtain analytical expressions for two typical cases, and demonstrate phase space evolution in the whole process by using the Wigner function. This method is valid for both classical atomic gas and Bose–Einstein condensates, and it is suited for temperature measurement on the space ultracold atomic physics platform, in which the ultra-narrow momentum distribution of atomic gas is of the order of 100 pK or even lower.

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