Spectral and Spatial Modulation of Optical Pump Beam for Mirrorless Optical Parametric Oscillation

Abstract

The advent of lasers in the 1960s as coherent light sources revolutionized nonlinear optics, enabling the exploration of phenomena driven by strong electromagnetic fields. Since then, a wide range of discoveries, such as sum frequency generation, optical parametric oscillation, and four-wave mixing (FWM) etc, have been extensively studied. This thesis focuses on Mirrorless Optical Parametric Oscillation (MOPO), a cavity-free process with high tunability, achieved through FWM, where phase matching is inherently satisfied by counter-propagating pump beams. By investigating the spectral and spatial modulation of pump beams, this work aims to advance the understanding and practical applications of MOPO in nonlinear optics. This process has been demonstrated in both χ (2) and χ (3) nonlinear media, leading to the generation and amplification of optical fields from noise due to the interaction of counter-propagating input fields in the nonlinear medium. The work presented in this thesis investigates the spectral and spatial modulation of optical pump beams used for MOPO. This thesis provides a basic theoretical and experimental overview, including the wave analysis of light, key nonlinear optical effects, and the derivation of nonlinear wave equations. It also addresses essential concepts in atomic physics, the application of acousto-optic modulators, and the 4-f imaging technique. The study further investigates the principles and properties of MOPO and explores experimental methods for generating multitone and time-shared pump beams using acousto-optic modulators. By focusing on spectral and spatial modulation, this research advances the understanding and practical applications of MOPO in nonlinear optics.