Polarization method for controlling a sign of electromagnetically-induced transparency/absorption resonances

Brazhnikov, D. V.; Тайченачев, А. В.; Yudin, V. I.

doi:10.1140/epjd/e2011-20112-6

Cited by 31 publications

(22 citation statements)

References 74 publications

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“…In this case, the absorption of both beams is increased and the Lamb dip is reversed. A similar effect has already been investigated for linear and elliptical polarizations in the Hanle configuration [20,21]. In this study, the monochromatic laser was tuned at resonance and the probe beam power was recorded versus the magnetic field.…”

Section: Pacs Numberssupporting

confidence: 55%

Doppler-free spectroscopy on the Cs D_1 line with a dual-frequency laser

et al. 2016

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We report on Doppler-free laser spectroscopy in a Cs vapor cell using a dual-frequency laser system tuned on the Cs D1 line. Using counter-propagating beams with crossed linear polarizations, an original sign-reversal of the usual saturated absorption dip and large increase in Doppler-free atomic absorption is observed. This phenomenon is explained by coherent population trapping (CPT) effects. The impact of laser intensity and light polarization on absorption profiles is reported in both single-frequency and dual-frequency regimes. In the latter, frequency stabilization of two diode lasers was performed, yielding a beat-note fractional frequency stability at the level of 3 × 10 −12 at 1 s averaging time. These performances are about an order of magnitude better than those obtained using a conventional single-frequency saturated absorption scheme. PACS numbers:In gas cell experiments, saturated absorption spectroscopy or Doppler-free spectroscopy [1,2] is an elegant technique to circumvent Doppler broadening and to allow the detection of natural-linewidth resonance dips in the bottom of absorption profiles. This method, frequently used to stabilize the frequency of a laser to a particular atomic line, is applied in atomic frequency standards [3], magnetometers [4], laser-cooling experiments [5] or atom interferometry. Laser fractional frequency stability in the 10 −13 −10 −11 range at 1 s integration time can be obtained by combining saturated absorption techniques and narrow-linewidth diode lasers [6][7][8][9][10]. In a common saturated absorption scheme, two counter-propagating laser beams of same frequency, a pump-beam and a probe beam, derived from a single laser beam, overlap one another in an atomic vapor cell. Since both beams have the same frequency, the Doppler effect brings different velocity groups into resonance with each beam. On resonance, only atoms presenting zero velocity along the light propagation axis actually experience the two beams with the same laser frequency. If the pump-beam intensity is high enough, the ground state is depleted and therefore the absorption of the probe beam is reduced compared to the case without pump beam. In this case, a so-called Lamb dip, with lorentzian profile, appears at the resonance frequency of the atomic transition in the bottom of a gaussian Doppler-broadened absorption profile. The full-width at half maximum (FWHM) of the Dopplerfree Lamb dip can be at low laser intensity as small as the natural linewidth of the atomic transition (4.6 MHz for the Cs D 1 line). This process is relatively easy to understand in the case of a simple two-level atom with a single-frequency laser system. In real experience, alkali atoms exhibit a complex multi-level energy structure with hyperfine structure splitting and numerous Zeeman sub-levels, especially in the Cs case (see Fig. 1). Such multi-level structures can lead, under appropriate conditions, to a sign reversal of saturation resonances [11][12][13].In the present article, we report on a Doppler-free laser frequency s...

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Section: Pacs Numberssupporting

confidence: 55%

Doppler-free spectroscopy on the Cs D_1 line with a dual-frequency laser

et al. 2016

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“…The dip can be observed (dashed black line) when dark states NC 1 ñ | and NC 2 ñ | are close to each other (case of parallel polarizations, see figures 2(a) and 9(d). Note that a similar effect under a pump-probe regime was discussed in references [35,38]. Figure 19(b) reflects the influence of the openness of the Λ-scheme.…”

Section: Zeeman Cpt Statessupporting

confidence: 66%

“…As explained above, this resonance peak is due to the existence of atoms in dark states that vanish at higher magnetic field strength. The reported spectra represent the regular magneto-optical Hanle resonances observed with counter-propagating light waves [35]. The weakness of the 4-4′ transition explains why the amplitude and linewidth of the central peak are smaller for this transition.…”

Section: Single-frequency Regime: Zeeman Cptsupporting

confidence: 55%

High-contrast sub-Doppler absorption spikes in a hot atomic vapor cell exposed to a dual-frequency laser field

et al. 2017

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The saturated absorption technique is an elegant method widely used in atomic and molecular physics for high-resolution spectroscopy, laser frequency standards and metrology purposes. We have recently discovered that a saturated absorption scheme with a dual-frequency laser can lead to a significant sign reversal of the usual Doppler-free dip, yielding a deep enhanced-absorption spike. In this paper, we report detailed experimental investigations of this phenomenon, together with a full indepth theoretical description. It is shown that several physical effects can support or oppose the formation of the high-contrast central spike in the absorption profile. The physical conditions for which all these effects act constructively and result in very bright Doppler-free resonances are revealed. Apart from their theoretical interest, results obtained in this manuscript are of great interest for laser spectroscopy and laser frequency stabilization purposes, with applications in laser cooling, matterwave sensors, atomic clocks or quantum optics. the atomic resonant frequency, the two counter-propagating waves drive different atom groups (of respective axial velocities v + and v -) due to the Doppler shift, which yields the Doppler profile. By contrast, when the frequency detuning is being scanned near the resonance frequency, the two waves act on the same group of atoms with v 0 » . Each wave reduces the absorption experienced by the other. Consequently, one can observe a Doppler-free dip in the absorption profile of one wave or a reduction in total fluorescence of the cell. This dip, with Lorentzian profile and natural linewidth, is known as the Lamb dip, or as saturated absorption resonance (SAR). It can be several orders of magnitude narrower than the Doppler-broadened spectrum in which it sits. A simple two-level scheme (with non-degenerate energy levels) can also exhibit SAR as a single peak or with a more complex shape such as those induced by the recoil effect [17][18][19], high-order spatial harmonics of atomic polarization [20] or peculiarities of the Doppler effect for open atomic transitions [21]. Multilevel atoms can exhibit a complex energy-level structure involving fine and hyperfine splittings and Zeeman (magnetic) sublevels. This complex structure yields complex optical pumping processes, justifying for example the detection of cross-over resonances in saturated absorption spectra or, under appropriate conditions, a sign reversal of saturation resonances [22][23][24][25][26][27].In a recent paper [28], an unexpected deep and narrow reversed spike (strong absorption peak) was observed in a saturated absorption experiment using a dual-frequency laser. The experiment was performed on a Cs vapor cell. The laser carrier frequency was tuned on the Cs D 1 line, with a frequency difference between the two firstorder sidebands equal to the hyperfine splitting (HFS) of the ground state. This phenomenon was applied to improve by about one order of magnitude the fractional frequency stability of a diode laser compared...

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“…Therefore, the achievement is still a significant issue in the MM-A researches. In spite of numerous studies, many issues remain to be explored, for example, to relax the working conditions and to increase the number of absorption peaks and the absorption bandwidth [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], as well as to switch the absorption properties [14,25] from microwave to infrared frequencies, because of significant impact in the field of solar cells [26], photodetectors [27], sensors [28], imaging devices [29] and thermal emitters [30].…”

Section: Introductionmentioning

confidence: 99%

Multi-band metamaterial absorber based on the arrangement of donut-type resonators

Park¹,

Pham²,

Rhee³

et al. 2013

Opt. Express

317

133

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We propose multi-band metamaterial absorbers at microwave frequencies. The design, the analysis, the fabrication, and the measurement of the absorbers working in multiple bands are presented. The numerical simulations and the experiments in the microwave anechoic chamber were performed. The metamaterial absorbers consist of an delicate arrangement of donut-shape resonators with different sizes and a metallic background plane, separated by a dielectric. The near-perfect absorptions of dual, triple and quad peaks are persistent with polarization independence, and the effect of angle of incidence for both TE and TM modes was also elucidated. It was also found that the multiple-reflection theory was not suitable for explaining the absorption mechanism of our investigated structures. The results of this study are promising for the practical applications.

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Polarization method for controlling a sign of electromagnetically-induced transparency/absorption resonances

Cited by 31 publications

References 74 publications

Doppler-free spectroscopy on the Cs D_1 line with a dual-frequency laser

Doppler-free spectroscopy on the Cs D_1 line with a dual-frequency laser

High-contrast sub-Doppler absorption spikes in a hot atomic vapor cell exposed to a dual-frequency laser field

Multi-band metamaterial absorber based on the arrangement of donut-type resonators

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