Developing a quantum control scheme for the detection of high energy charged particles using the strong non-linear optical response response of atomic media in EIT states.

The strong non-linear optical response of atomic systems in EIT states is considered as a means to detect the presence of small perturbations to steady states. For the 3 level system, expressions for the group velocity and group velocity dispersion (GVD) were derived and a quantum control protocol was established to account for the change in the chirp spectrum of a probe pulse when the steady state was perturbed. This was applied to the propagation of slow Cherenkov polaritons in the medium due to the passage of a train of high-energy charged particles (HEcPs). The choice of the initial steady state with focus on the slow light condition and strong narrowly confined dispersion, equated to the continuous trapping of Cherenkov polaritons in the medium along a narrow group cone, allowing for non-trivial fields to accumulate. Considering another medium prepared for detection of radiation, sweeping of the control field and detuning parameters in the field-atom parameter space showed the presence of optimal regions to maximize the first order perturbation in the coherences- thus creating controlled changes in the optical responses that modify the chirp spectra of probe pulses. The results from this investigation show similar analogues in complex systems beyond the scope of this investigation. Systems such as semiconductors and 2D metals coupled to cavity radiation are considered as future branches for investigation.