Abstract
Few-to-single cycle near-infrared pulses, with temporal envelop widths less than ten femtoseconds (1fs = 10-15 s), have received great attention for their ultrahigh time resolution, ultrabroad spectral range and enormous peak intensity. They have been used in versatile applications, such as time-resolved spectroscopy and high harmonic generation of isolated EUV (extreme ultraviolet radiation) /X-ray pulses. However, ultrashort optical pulses are prone to temporally broadened due to the dispersion of optical mediums, which introduce a spectral phase modulation upon the input pulse. Therefore, detailed information (amplitude and phase profiles) of ultrashort optical pulses is highly significant in terms of maintenance and control of the ultrafast waveforms in some applications. There have been a couple of measurement techniques that can retrieve the electric field of few-cycle pulses. Most of them rely on the nonlinearly converted signal of the unknown optical pulse. In this thesis, we proposed and experimentally demonstrated the shaper-assisted modified interferometric field autocorrelation (MIFA) method for retrieving the spectral phases of weak (16 pJ) 7.2 fs nearly transform-limited pulse and tailored waveforms at 800 nm by using a 40-um-thick BBO. Experiment results confirm the high accuracy and reproducibility of this method. Our method is attractive in terms of: (1) inherently high sensitivity arisen from using thick nonlinear crystal, (2) free of time-consuming iterative data inversion, (3) access to the desired waveform at the point of experiment by integration of measurement and shaping, (4) high stability against environmental perturbation due to the nearly common-path configuration.