In this manuscript, we observed narrowing of electromagnetically induced transparency (EIT) spectral width by using superimposed Laguerre-Gaussian (LG) beams for coupling light. EIT with narrow transparency width has a potential application towards slow light for quantum memory devices. LG beams of σ + and σ − polarization are superimposed and used as coupling light for an EIT experiment. A theoretical model is discussed using a semi-classical treatment and the experimental part confirms the narrowing of EIT width for higher values of 'l'.
We investigate both experimentally and theoretically the cascade electromagnetically induced transparency(EIT) in 5S1/2 − 5P3/2 − 5D5/2 configuration in 87 Rb atomic vapor medium in the presence of vortex coupling Laguerre Gaussian(LG) light. We demonstrated Doppler free double resonance EIT structure in cascade configuration and observed transmission spectra for H-H and σ+-σ+ polarized probe and coupling lights. We demonstrate that the double resonance structure can be identified by two photon transition probabilities and it is found to be F” = 2 and F” = 3. By considering coupling LG light, several polarization combinations are taken into account, and their effects on amplifying and diminishing the EIT resonances are demonstrated experimentally. In order to understand the polarization effects of vortex coupling light on EIT spectrum in a degenerate multilevel atomic system, a theoretical model is developed by considering a simplified double hut level structure. Semi-classical density matrix analysis is used to understand the dynamics and also to establish the enhancement and reduction of EIT peak height with coupling light polarizations. The impact of two photon transition probabilities polarization combinations and relative orientations of probe and coupling lights in degenerate multilevel atomic systems leads to modification of EIT resonances significantly. We establish quantitative agreement between our theory and experimental results.
In this work, we have theoretically studied the four-level atomic system for the measurement of a microwave (MW) field. We employed the electromagnetically induced transparency (EIT) technique for finding the MW field in the presence of a Laguerre–Gaussian (LG) beam as a coupling light. We have shown that, by the application of LG modes, narrower dips for the probe absorption spectrum can be generated, which can be easily identified and gives better resolution compared with the Gaussian mode. An exact location of dips in the probe absorption spectrum is found, and it is useful in the measurement of MW fields. We have estimated the FWHM of the probe absorption spectrum for Gaussian and LG coupling cases as
3.74
×
10
5
H
z
and
1.07
×
10
5
H
z
, respectively. Based on FWHM, we have found that minimum change in MW electric field in the order of
3.32
µ
V
c
m
−
1
will be detectable in the case of the LG mode as a coupling beam.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.