High Contrast Electromagnetically Induced Transparency in a Nitrogen Filled Rb Vapour Cell
TL;DR: In this paper, the authors observed the electromagnetically induced transparency (EIT) spectra inside a nitrogen filled Rb vapour cell (Rb-N2) in a five-level Λ-type system of D2 transition of Rb atom.
Abstract: We observe the electromagnetically induced transparency (EIT) spectra inside a nitrogen filled Rb vapour cell (Rb-N2) in a five-level Λ-type system of D2 transition of Rb atom. The high contrast EIT resonance in buffer gas filled Rb cell is obtained under our experimental conditions. The effect of velocity changing coherence preserving collisions to obtain the contrast resonance in buffer gas cell has been discussed. We measured the dependence of EIT width and height on pump intensity and find that the EIT width (FWHM) and peak height have a linear dependence on pump intensity. Our experimental results show that the presence of N2 buffer gas reduces the power broadening of the observed resonances.
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TL;DR: Efficient all-optical modulation using Rb vapor confined to a hollow-core photonic bandgap fiber is demonstrated, corresponding to 23 photons per atomic cross section lambda(2)/(2pi).
Abstract: We demonstrate efficient all-optical modulation using Rb vapor confined to a hollow-core photonic bandgap fiber. The intensity of a signal field participating in the four-wave-mixing process is modulated using a weak switching field. We observe 3dB of attenuation in the signal field with only 3600 photons of switching energy, corresponding to 23 photons per atomic cross section λ2/(2π). Modulation bandwidths as high as 300MHz are observed.
24 citations
TL;DR: In this paper, the authors studied electromagnetically induced transparency (EIT) in diatomic cesium molecules in a vapor cell by using tunable diode lasers.
Abstract: We have studied electromagnetically induced transparency (EIT) in diatomic cesium molecules in a vapor cell by using tunable diode lasers We have observed a sub-natural Λ-resonance in absorption molecular band B
1Π
u
− X
1Σ
+
at different cesium vapor pressures The width of the EIT resonance shows a linear dependence on a cesium vapor pressure
14 citations
TL;DR: In this article, the experimental observations of double EIT and enhanced EIT signal in a combination of Λ- and V-type multi-level system of the D2 transition of 85Rb atoms interacting with three laser fields are reported.
Abstract: We report the experimental observations of double EIT and enhanced EIT signal in a combination of Λ- and V-type multi-level system of the D2 transition of 85Rb atoms interacting with three laser fields. The EIT formation under a Λ-type and V-type systems is also observed separately. It is found that the EIT width in a V-type system becomes narrower than the Λ-type system. Also the effect of frequency detuning of the control laser on the probe absorption profile is studied in presence of Λ- and V-type EIT systems.
11 citations
TL;DR: In this article, a variety of coherent non-linear resonances were investigated experimentally in the presence of a standing wave pump field for the D2 transition of both Rb isotopes.
4 citations
TL;DR: In this paper, the authors studied the phenomenon of electromagnetically induced transparency (EIT) of 87Rb vapor with a buffer gas in a magnetic field at room temperature and found that the spectral lines caused by the velocity selective optical pump effects get much weaker and wider when the sample cell is mixed with a 5-Torr N2 gas while the EIT signal is kept almost unchanged.
Abstract: We have studied the phenomenon of electromagnetically induced transparency (EIT) of 87Rb vapor with a buffer gas in a magnetic field at room temperature. It is found that the spectral lines caused by the velocity selective optical pump effects get much weaker and wider when the sample cell is mixed with a 5-Torr N2 gas while the EIT signal is kept almost unchanged. A weighted least-square fit is also developed to remove the Doppler broadening completely. This spectral method provides a way to measure the Zeeman splitting with high resolution, for example, the Λ-type EIT resonance splits into four peaks on the D2 line of 87Rb in the thermal 2-cm vapor cell with a magnetic field along the electric field of the linearly polarized coupling laser. The high-resolution spectrum can be used to lock the laser to a given frequency by tuning the magnetic field.
3 citations
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TL;DR: In this article, the authors observed the transformation of the electromagnetically induced transparency (EIT) resonance into an absorption resonance in a ε-Lambda interaction configuration in a cell filled with $π{Rb} and a buffer gas.
Abstract: We observe transformation of the electromagnetically induced transparency (EIT) resonance into an absorption resonance in a $\ensuremath{\Lambda}$ interaction configuration in a cell filled with $^{87}\mathrm{Rb}$ and a buffer gas. This transformation occurs as one-photon detuning of the coupling fields is varied from the atomic transition. No such absorption resonance is found in the absence of a buffer gas. The width of the absorption resonance is several times smaller than the width of the EIT resonance, and the changes of absorption near these resonances are about the same. Similar absorption resonances are detected in the Hanle configuration in a buffered cell.
46 citations
TL;DR: In this paper, the authors presented two techniques to lock a laser frequency on an atomic transition line by using an electromagnetically induced transparency (EIT) signals, which give optical and electric feedback.
Abstract: We present two techniques to lock a laser frequency on an atomic transition line by using an electromagnetically induced transparency (EIT) signals, which give optical and electric feedback. We employed these methods to the D2 line of 87Rb atoms. Spectral characteristics of subnatural linewidth EIT allow us to improve frequency stability. By optical feedback of EIT signals, we were able to obtain locking bandwidths of 12 MHz, while frequency stability was 5×10−13 at best after 100 s of integration using a frequency modulation technique.
39 citations
TL;DR: In this article, the formation of a coherent population trapping resonance in a finite-size vapour cell without a buffer gas was investigated, and the authors demonstrated the mechanisms of the resonance narrowing: an analogue of the Dicke effect and light-induced narrowing.
Abstract: We have investigated theoretically the formation of a coherent population trapping resonance in a finite-size vapour cell without a buffer gas. We have demonstrated the novel mechanisms of the resonance narrowing: an analogue of the Dicke effect and light-induced narrowing. In the light-induced narrowing regime the parameters of the coherent population trapping resonance weakly depend on the cell size and the type of coating.
19 citations
TL;DR: In this article, the experimental observation of electromagnetically induced transparency (EIT) in a Doppler broadened rubidium vapour at room temperature for different probe intensities at a fixed pump intensity in a five-level Λ-type system formed by the D2 transition of 85Rb.
Abstract: We report the experimental observation of electromagnetically induced transparency (EIT) in a Doppler broadened rubidium vapour at room temperature for different probe intensities at a fixed pump intensity in a five-level Λ-type system formed by the D2 transition of 85Rb. For a constant pump intensity, we find that the EIT width and height change with the variation of probe intensity. We observe a nonlinear variation of the height of the EIT peak and a linear variation of the width (FWHM) of the EIT signal with probe intensity. In the Doppler broadened multilevel system, we also observe the velocity selective dips along with the EIT signal. A numerical simulation of the probe response signal based on density matrix representation in a five-level system is carried out to reproduce the experimentally observed spectra.
12 citations
TL;DR: In this article, the authors investigated the spectra of the electromagnetically induced transparency (EIT) when a cell is filled with a buffer gas and showed that the buffer gas can induce a narrower spectra line and steeper dispersion than those of the usual EIT case in a homogeneous and Doppler broadened system.
Abstract: We have investigated the spectra of the electromagnetically induced transparency (EIT) when a cell is filled with a buffer gas. Our theoretical results show that the buffer gas can induce a narrower spectra line and steeper dispersion than those of the usual EIT case in a homogeneous and Doppler broadened system. The linewidth decreases with the increase of the buffer gas pressure. This narrow spectra may be applied to quantum information processing, nonlinear optics and atomic frequency standard.
6 citations