Effects of chirped laser pulses on nonclassical correlations and entanglement of photon pairs

Abstract

We study the effects of arbitrary laser pulse excitations on quantum correlation, entanglement, and the role of quantum noise. The transient quantities are computed exactly using a method that provides exact solutions of the Langevin field operators for photon pairs produced by a double Raman atom driven by laser pulses. Short pulses with appropriate chirping, delay, and/or detuning can generate broadband photon pairs and yield results that provide insights on how to generate very large nonclassical correlation. We find that short pulses are not favorable for entanglement. Photon correlation and entanglement are favored by exclusively two different initial conditions. We find rapid variations of entanglement with pulse width and strength. Explanation is given based on the pulse area concept and the phase-sensitive nature of entanglement. Analysis of results reinforces our understanding of the two nonclassical concepts and the nature of quantum noise.