Optical bistability in one dimensional doped photonic crystals with spontaneously generated coherence

TL;DR

This paper explores how spontaneously generated coherence enhances optical bistability in doped photonic crystals, enabling lower thresholds and improved control of hysteresis properties for potential optical switching applications.

Contribution

It demonstrates that spontaneously generated coherence significantly reduces the threshold for optical bistability in doped photonic crystal defect layers, with tunable hysteresis characteristics.

Findings

Spontaneously generated coherence enhances Kerr nonlinear response.

Threshold for optical bistability can be reduced by three orders of magnitude.

Control of hysteresis loop size and contrast via Rabi frequency and detuning.

Abstract

We investigate optical bistability in a multilayer one-dimensional photonic crystal where the central layer is doped with $\Lambda$-type three level atoms. We take into account the influence of spontaneously generated coherence when the lower atomic levels are sufficiently close to each other, in which case Kerr-type nonlinear response of the atoms is enhanced. We calculate the propagation of a probe beam in the defect mode window using numerical nonlinear transfer matrix method. We find that Rabi frequency of a control field acting on the defect layer and the detuning of the probe field from the atomic resonance can be used to control the size and contrast of the hysteresis loop and the threshold of the optical bistability. In particular we find that, at the optimal spontaneously generated coherence, three orders of magnitude lower threshold can be achieved relative to the case without the coherence.