arXiv subjects

L. Windholz

Publications and source records attributed to L. Windholz.

4 recordsLinked to original sources

arXiv2009

Quantitative study of desctructive quantum interference effect on the linklin CPT

We investigate experimentally and theoretically the Coherent Population Trapping (CPT) effect occurring in 87Rb D1 line due to the interaction with linearly polarized laser light (lin||lin CPT). In this configuration the coherence has a quadrupol like nature and is strongly influenced by the hyperfine structure of the excited state; consequently the quantum interference between CPT states is an essential feature of this interaction scheme. We study the lin||lin CPT signal as a function of the laser optical detuning. The comparison between experimental and theoretical results allows us to quantify the contribution from different CPT states to the total signal. Based on these results we investigate the signal depending on both the pressure broadening of the optical transition and the laser linewidth, and we find in which conditions the laser linewidth does not degrade the amplitude of the lin||lin CPT.

quant-ph↗

arXiv2004

Phase correlation of laser waves with arbitrary frequency spacing

The theoretically predicted correlation of laser phase fluctuations in Lambda-type interaction schemes is experimentally demonstrated. We show, that the mechanism of correlation in a Lambda scheme is restricted to high frequency noise components, whereas in a double-$Λ$ scheme, due to the laser phase locking in closed-loop interaction, it extends to all noise frequencies. In this case the correlation is weakly sensitive to coherence losses. Thus the double-Lambda scheme can be used to correlate e.m. fields with carrier frequency differences beyond the GHz regime.

quant-ph↗

arXiv2000

Efficient Raman Sideband Generation in a Coherent Atomic Medium

We demonstrate the efficient generation of Raman sidebands in a medium coherently prepared in a dark state by continuous-wave low-intensity laser radiation. Our experiment is performed in sodium vapor excited in $Λ$ configuration on the D$_{1}$ line by two laser fields of resonant frequencies $ω_{1}$ and $ω_{2}$, and probed by a third field $% ω_{3}$. First-order sidebands for frequencies $ω_{1}$, $ω_{2}$ and up to the third-order sidebands for frequency $ω_{3}$ are observed. The generation starts at a power as low as 10 microwatt for each input field. Dependencies of the intensities of both input and generated waves on the frequency difference ($ω_{1}-ω_{2}$), on the frequency $ω_{3}$ and on the optical density are investigated.

quant-ph↗

arXiv1996

Coherent Population Trapping with Losses on the Sodium D1 Line Hanle Effect

We consider the coherent population trapping phenomenon in a thermal sodium atomic beam. We compare the different coherent population trapping schemes that can be established on the D1 line using the Zeeman sublevels of a given ground hyperfine state. The coherent population trapping preparation is examined by means of a Hanle effect configuration. The efficiency of the coherent population trapping phenomenon has been examined in presence of optical pumping into hyperfine levels external to those of the excited transition. We show that both the contrast and the width of the coherent population trapping resonance strongly decrease when the optical pumping rate is increased. In the experiment, the loss rate due to optical pumping has been controlled by means of a laser repump of variable intensity.

physics.atom-ph↗