光波助變放大器與半導體脈衝塑形現象之飛秒非線性光學研究

Abstract

This thesis presents investigations of nonlinear optical interaction between femtoseond laser pulses and materials. The first part focuses on femtosecond optical parametric amplification. A high power femtosecond optical parametric amplifier is demonstrated. A complete simulation approach is developed and demonstrated to successfully describe the output characteristics of the real optical parametric amplifier. This simulation approach is used as an analytic tool to investigate the dynamical interaction between material dispersion and three-wave nonlinear coupling during the amplification process. Several critical issues are addressed. A designed procedure of femtosecond optical parametric amplifiers is proposed. The second part focuses on the pulse-shaping phenomena of semiconductors. A high precision femtosecond laser pulse measurement technique is demonstrated. It is frequency-resolved optical gating based on two-beam coupling. Its precision and accuracy is examined before applying it to subsequent experiments. Pulse-shaping effects of gallium arsenide and semiconductor saturable absorber mirror have been successfully unveiled. Dielectric functions modified by photoexcited carriers are used to interpret experimental results. Observed pulse-shaping effects of semiconductor saturable absorber mirror are compared to theoretical prediction.