Double cavity induced transparency in a Y-type atomic system based on cavity QED photons

We show that a fully quantum-mechanical model consisting of a four-level atom with Y-type atomic structure inside a three-mode cavity can exhibit double cavity induced transparency (CIT). In this model, it is cavity photons that induce the transparency, and there is no need to use external classical fields. As this double-CIT model involves several atomic levels, we adapt the wavefunction approach as a quantum-jump description of dissipation to derive an analytical expression for the steady-state linear susceptibility of a weak cavity field. We then use this analytical expression to investigate the dependence of the CIT transparency windows on the detuning of the coupling fields, intensities of the cavity fields and the cavity linewidths. We also have tested the analytical results by numerically integrating the full set of optical Bloch equations for the atomic density-matrix elements.