[email protected], [email protected] 

We present the theoretical analysis of the time delay and transmittance properties of an integrated structure composed of Atomic Vapor embedded in a Micro Ring Resonator (MRR).

The integration of an atomic system with a MRR for realization of slow and fast light applications has very promising prospects since both systems are dispersive in nature, and thus have distinct features in terms of their complex transmission. Moreover, both systems are well exploited and understood for over a decade and are used separately in numerous applications [1-2]. Following the latest achievements in confining atomic vapor on chip [3], the construction of such a hybrid system may become possible. The objective of this work is to question whether it's possible, and to what extent, to achieve slow or fast light properties in such a combined system of Alkali Vapor and Optical resonators.

We theoretically analyze and simulate a MRR composed of an Alkali Vapor which is embedded in the waveguide of the resonator (either in the core or in the cladding), as an on chip platform for slow and fast light. Specifically, we are looking at a realistic scenario in which the atomic resonance line width is smaller than the structural line width. This is achieved, in a relatively simple manner (as opposed to electromagnetically induced transparency, EIT, setups) using alkali vapor optical absorption lines. Such absorption lines are for instance the well known D1 or D2 optical transitions of Rubidium or Cesium.

MRRs exhibit both slow and fast light accompanied with strong absorption around their critical coupling. Absorptive Atomic vapor, exhibits fast light consequently from its anomalous dispersion. Here we show that upon integrating the optical resonance with the atomic resonance, one can achieve enhanced fast and slow light, whilst the latest is accompanied with reduced absorption.  Moreover, we demonstrate that such a system can alter the time delay sign of the embedded material turning from fast light to slow light, depending on the coupling coefficient of the MRR. The proposed system has promising features due to its reduced footprint, tunability, bandwidth and relatively high delay-absorption product. Effort to realize and characterize such a device is under process.

References

1. J. Vanier, "Atomic clocks based on coherent population trapping: a review," Appl. Phys. B 81, 421-442 (2005)
2. V. R. Almeida, C. A. Barrios, R. R. Panepucci, and M. Lipson, "All-optical control of light on a silicon chip," Nature, vol. 431, no. 7012, pp. 1081-1084, October 2004
3. W. Yang, D. B. Conkey, B. Wu, D. Yin, A. R. Hawkins, and H. Schmidt, "Atomic spectroscopy on a chip," Nature Photonics, vol. 1, no. 6, pp. 331-335, June 2007