Velocity-selective resonance dips in the probe absorption spectra of Rb D2 transitions induced by a pump laser

It is shown that the pump-probe spectroscopy of Λ-type system for the D2 transition of 87Rb exhibits additional absorption enhancement peaks due to velocity selective optical pumping along with the electromagnetically induced transparency (EIT). The separation of these peaks is consistent with the hyperfine splitting of the upper levels. For 85Rb the peaks are not clearly discernible since the hyperfine splitting is much smaller.

Section: Methodsmentioning

confidence: 99%

Velocity selective optical pumping effects and electromagnetically induced transparency for D₂transitions in rubidium

Chakrabarti¹,

Pradhan²,

Ray³

et al. 2005

“…It is well known that when two laser fields drive an atomic medium simultaneously, a variety of interesting nonlinear optical phenomena will occur, such as coherent population trapping (CPT) [16][17][18][19], electromagnetically induced transparency (EIT) [20][21][22][23][24][25][26], electromagnetically induced absorption (EIA) [27], amplification without inversion (AWI) [28], velocity transfer effect [29], etc. Apart from the coherence resonances such as CPT, EIT and EIA, different nonlinear resonances arising from optical pumping and saturation effects can also be observed in a multi-level system [30][31][32][33][34][35][36][37][38][39][40]. Such as velocity selective optical pumping (VSOP) produced in a Λtype system [30][31][32][33][34][35], velocity selective resonance (VSR) produced in a V-type system [36], etc.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the coherence resonances such as CPT, EIT and EIA, different nonlinear resonances arising from optical pumping and saturation effects can also be observed in a multi-level system [30][31][32][33][34][35][36][37][38][39][40]. Such as velocity selective optical pumping (VSOP) produced in a Λtype system [30][31][32][33][34][35], velocity selective resonance (VSR) produced in a V-type system [36], etc. In the traditional methods of nonlinear resonance spectroscopy in a multi-level system co-propagating pump and probe beams are used to observe induced transmission profile of the probe.…”

Section: Introductionmentioning

confidence: 99%

A global crossover saturated-absorption spectroscopy induced by dual-frequency laser

Chang

Pan

Shang

et al. 2020

We report on a global crossover saturated-absorption spectroscopy (SAS) of Cs D2 transition using a dual-frequency laser field with a frequency difference of less than the Doppler width. With two pairs of dual-frequency laser beams counter-propagating through the vapor cell, the line shape and non-linear features observed in the transmission spectra of the probe beam change with the frequency difference of the dual-frequency laser. The superficially complicated transmission signal includes two sets of common single-frequency SAS and several velocity-selective resonances (VSRs), we call these VSR peaks ‘global crossover SAS’. This phenomenon is explained by VSR effect. The global crossover SAS is formed by the atomic velocity groups resonance with both the initial and modulated laser fields, which are counter-propagated. Moreover, the global crossover SAS dips having the separation of allowed hyperfine transitions move along with the two sets of common single-frequency SAS while the frequency difference of the dual-frequency laser is changed. This indicates a resonance between the velocity shifted pump laser frequency and the velocity shifted probe laser frequency. The results obtained in this system are of great interest for laser spectroscopy. Furthermore, the application of the counter-propagating laser beams in the dual-mode regime increase the number of atoms that effectively interact with the field, hence, this scheme has a potential advantage for laser frequency stabilization.

“…Apart from the coherence resonances such as EIT and EIA, different nonlinear resonances based on optical pumping and saturation effects due to the pump/control laser can also be observed in a multi-level system for the D 2 line of 85 Rb atoms [24][25][26][27]. The D 2 line (5S 1/2 → 5P 3/2 ) of 85 Rb atoms has two ground hyperfine levels (5S 1/2 , F = 2, 3) and four excited hyperfine levels (5P 3/2 , F = 1, 2, 3, 4).…”

Section: Introductionmentioning

confidence: 99%

“…These excited atoms will burn holes in the population distribution curve in the ground hyperfine level which is also coupled by the probe laser. As a result the probe laser frequency scanning will show reduction in absorption at Doppler shifted frequencies due to the presence of these holes and exhibit velocity selective resonance (VSR) [27] peaks in the probe transmission profile. In addition to the pump laser field, if we apply another laser field (called 'control laser') to the atomic system, then the control laser field also forms a -or V-type system along with the common probe laser field depending on the atom-laser coupling scheme.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear resonances caused by coherent, optical pumping and saturating effects in the presence of three laser fields for the⁸⁵Rb-D₂line

Hossain

Mitra

Poddar

et al. 2011

Atomic coherence resonances such as electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA) signals are observed in a Doppler broadened multi-level system for the D 2 line of 85 Rb atoms in a vapour cell considering different types of atom-laser coupling schemes. Besides the coherence resonances, the nonlinear resonances like velocity selective optical pumping (VSOP) dips and velocity selective resonances (VSR)are also observed for the non-zero velocity selective groups of atoms. In the presence of pump, control and probe laser fields, we observe two EIT signals in a double -type system and two EIA signals in a double V-type system. We are able to see the EIA signal for the non-zero velocity group of atoms when the pump laser is locked with an open transition by a small red detuning. We also report the experimental observation of simultaneous EIT and EIA signals in a ( +V)-type system. The effect of frequency tuning of the control laser is also studied in the presence of the frequency locked pump laser. A simple theoretical analysis explains the experimental results.