Effects of Chirped Laser Pulses on Nonclassical Correlation and Entanglement of Photon Pairs from Single Atom

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. The quantity was previously found to be phase-sensitive and this is used with the pulse area concept to explain the rapid variations of entanglement with pulse width and strength. Photon correlation and entanglement are favored by exclusively two different initial conditions. Analysis reinforces our understanding of the two nonclassical concepts.