Interference between electromagnetically induced transparency and two-step excitation in three-level ladder systems

Abstract

We have performed electromagnetically induced transparency (EIT) and two-photon absorption experiments in ladder-type three-level systems in a hot sodium atomic vapor, using the 3S 1/2 -3P 1/2 -4D 3/2 , 3S 1/2 -3P 3/2 -4D 3/2,5/2 , 3S 1/2 -3P 1/2 -5S 1/2 , and 3S 1/2 -3P 3/2 -5S 1/2 transitions. In particular, in the most pronounced 3S 1/2 -3P 1/2 -4D 3/2 system, we have observed quite unique spectral line shapes that are superpositions of sharp dips and peaks, in contrast to ordinary EIT spectra. The peaks and dips have apparently different physical origins and the line shape can be interpreted as the interference between EIT and two-step excitation.

Electromagnetically induced polarization rotation in Na vapor

“…Recently we have reported on very unique double Lorentzian EIT spectra in three-level ladder systems in a hot Na vapor [20], in clear contrast to Rb ladder EIT that exhibits single Lorentzian line shapes [21][22][23]. This paper is a continuation of our previous paper and now we apply the same system for EIPR study.…”

Pulsed ac Stark shifts monitored by Raman Ramsey fringes in sodium vapor

“…1(a) and is similar to our previous work for RRF [5,15]. A singlefrequency tunable ring dye laser (RDL#1, Coherent Radiation CR699-21), tuned to the 3S 1∕2 − 3P 1∕2 D1 transition at 589.6 nm, provided probe and coupling pulses having the same intensity, pulse timing, and pulse width with a fixed pulse repetition time of 250 μs.…”

Transmittance signal in real ladder-type atoms

“…Ladder-type EIT has been demonstrated in many kinds of atoms, including sodium [13], rubidium [14][15][16][17][18][19], and cesium [20]. In the case of ladder-type atomic systems in alkali-metal atoms, the two-photon atomic coherence and the optical-pumping effects cannot be distinguished from changes in the EIT spectrum; this is because the frequency of double-resonance optical pumping (DROP) occurs under the conditions of two-photon resonance in a similar manner to that of EIT [21].…”

“…In the case of ladder-type atomic systems in alkali-metal atoms, the two-photon atomic coherence and the optical-pumping effects cannot be distinguished from changes in the EIT spectrum; this is because the frequency of double-resonance optical pumping (DROP) occurs under the conditions of two-photon resonance in a similar manner to that of EIT [21]. A further, serious problem is that the transmittance signal due to optical pumping is often confused with EIT in many studies of ladder-type EIT in alkali-metal atoms [13][14][15][16][17][18][19][20]. The basis of this misunderstanding is that in EIT real ladder-type atoms are modeled as simple three-level atomic systems without including the DROP effect [19].…”

“…However, many papers' theoretical work is simply based on a simplified three-level model, and more detailed studies which consider realistic atomicenergy levels, to the best of our knowledge, do not exist. For the interesting topic of discrimination of one-photon * hrnoh@chonnam.ac.kr † hsmoon@pusan.ac.kr and two-photon resonances in the EIT signals, there have been theoretical studies on three-level atoms [22][23][24] and experimental works on Na [13] and Rb [21]. It should be noted that the quantum-jump approach has been used for the probe response in the three-level atomic systems [25,26].…”