Two-Mode Squeezing in Stimulated Raman Scattering

We investigate the quantum correlations that develop between the Stokes and anti-Stokes fields in stimulated Raman scattering. The correlations of the fields are examined in two models: the cavity model where the fields are confined in a cavity environment and amplifier model where field propagation in space is included. Both the models are analytically solved in the non-depleted pump regime. Attention is focused on field correlations which produce two-mode squeezed light. There are three types of squeezing studied in this thesis: sum squeezing, difference squeezing and two-mode normal squeezing. We examine a cavity model which includes a loss mechanism. The phonon dynamics in this model is studied for its role in determining two-mode squeezing. By excluding the phonon dynamics in the model, we find that light, prepared initially in either a coherent or chaotic state, is sum -squeezed. The quantum correlations between the Stokes and anti-Stokes fields in the coherent state produce less background noise compared to the chaotic state. When the phonon dynamics is taken into account, we find sum squeezing, as well as normal squeezing, when the anti-Stokes coupling is larger than the Stokes coupling. In this case, the level of background noise in both the coherent and chaotic states are reduced compared to the previous case although the latter remains to have a noisier background than the former. In the amplifier model, we find that two distinct physical states evolve depending on the relative magnitude of the Stokes and anti-Stokes coupling. When the Stokes coupling dominates over the anti-Stokes coupling, the fields grow exponentially in time. When the anti-Stokes coupling is the dominant coupling, the magnitude of the fields become significantly lower and they reach an equilibrium in time. The quantum correlations which develop between the Stokes and anti-Stokes fields are sensitive to the physical state of the system. When the anti-Stokes coupling constant is larger, the quantum correlations exist in the form of normal squeezing and sum squeezing. In the other case, only sum squeezing is observed.