Spectral Shaping And Beam Quality Amelioration In CPA System

Over the past ten years, high-power ultra-shot pulse Ti: sapphire laser technologies based on chirped pulse amplifier(CPA) have been rapidly developed and a number of large facilities have been built, increasing peak power density and shorten pulse width are always pursued aim for scientists. This dissertation was based on a 10 TW/20 fs Ti: sapphire laser system built by ourselves. shortening compressed pulse width and increasing foused spot quality were studied, respectively.Through analyzing the reason of gain narrowing in regenerative amplifier, we using three experimental methods successfully restrain the gain narrowing in regenerative amplifier. Studied the theoretical basis for measuring the beam quality factor, effectively improve the system output beam quality by using spacial filter designing by ourselves. The main research topics included:1. The influence of gain-narrowing, gain-saturation, and self-phase modulation on the properties of the amplified chirped-pulse spectrum were investigated. Elaborated the main factor influence of the output spectra in the 10 TW/20 fs Ti:s laser system.2. By using an Acoustic-Optic Programmable Dispersive Filter(AOPDF) to compensate for gain narrowing in the regenerative amplifier and for residual phase errors of femtosecond pulse laser system. The resultant 20 fs/66 ran FWHM transform-limited compressed pulse are get from the laser system which capable of generating 35 fs/38 nm FWHM compressed pulse without additional shaping. Owing to independent and simultaneous control of amplitude and phase, AOPDF can efficiently compensate for gain narrowing in the regenerative amplifier and for phase distortions of the whole laser chain.3. The etalon designed by myself and the birefringent filter of quartz crystal were inserted into the Ti:s regenerative amplifier cavity for the...