Electromagnetically induced transparency in Raman gain for realizing a superluminal ring laser

Abstract

We describe an approach for realizing a superluminal ring laser using a single isotope of Rb vapor by producing electromagnetically induced transparency (EIT) in Raman gain. We show that by modifying the detuning and the intensity of the optical pump field used for generating the two-photon population inversion needed for generating Raman gain, it is possible to generate a dip in the center of the gain profile that can be tuned to produce a vanishingly small group index, as needed for making the Raman laser superluminal. We show that two such lasers, employing two different vapor cells, can be realized simultaneously, operating in counter-propagating directions in the same cavity, as needed for realizing a superluminal ring laser gyroscope. This technique, employing only one isotope, is much simpler than the earlier, alternative approach for realizing a superluminal Raman laser based on Raman gain and Raman dip in two isotopes [Zhou et. al, Opt. Express 27, 29738 (2019)10.1364/OE.27.029738]. We present both an approximate theoretical model based on four levels as well as the results of a model that takes into account all relevant hyperfine states corresponding to the D1 and D2 transitions in 85Rb atom. We also present experimental results, in good agreement with the theoretical model, to validate the approach.

Sagnac interferometry and the impact of conductivity-dependent Raman gain on rotary photon drag

“…Qamar et al [33] used the RG process for achieving sub-wavelength atomic localization. RG has also been employed in a super-luminal ring laser gyroscope [34].…”

Controllable fast light in quantum dot molecules assisted hybrid optomechanical system

“…In an interesting study, Chen et al [13] investigated, theoretically, the propagation of light in OMS with Bose Einstein condensate. Smith et al [14] studied the enhancement of Fast-light in optical cavity by polarization mode coupling, Sternfeld et al [15] use isotope of Rb vapor to obtain superluminal ring laser by describing electromagnetically induced transparency (EIT) phenomenon in Raman gain. Bacha et al [16] studied the fast light pulse propagation in an N-type Doppler broadened four level atomic system in double Raman gain.…”