Sternfeld Yael, Zhou Zifan, Scheuer Jacob, Shahriar S M
Opt Express. 2021 Jan 18;29(2):1125-1139. doi: 10.1364/OE.408683.
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. Express27, 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.
我们描述了一种通过在拉曼增益中产生电磁诱导透明（EIT），利用单一铷（Rb）同位素蒸汽实现超光速环形激光器的方法。我们表明，通过改变用于产生拉曼增益所需的双光子粒子数反转的光泵浦场的失谐量和强度，可以在增益谱的中心产生一个凹陷，该凹陷可根据使拉曼激光器超光速的需要进行调谐，以产生极小的群折射率。我们表明，可以同时实现两个这样的激光器，它们使用两个不同的蒸汽室，在同一腔体内沿相反方向运行，这是实现超光速环形激光陀螺仪所必需的。这种仅使用一种同位素的技术比早期基于两种同位素中的拉曼增益和拉曼凹陷来实现超光速拉曼激光器的替代方法要简单得多[周等人，《光学快报》27，29738（2019）10.1364/OE.27.029738]。我们给出了一个基于四能级的近似理论模型以及一个考虑了与85Rb原子中D1和D2跃迁相对应的所有相关超精细态的模型结果。我们还给出了与理论模型吻合良好的实验结果，以验证该方法。
