Research On Reconstruction Algorithm For Single-shot Spatiotemporal Measurement Of Ultrashort Pulses

Ultrafast and Ultra-intense lasers have been further developed in recent years,towards the trend of higher peak power and narrower pulse width.It is critical to study the interaction between light and matter,and to explore new physical phenomena and laws under extreme conditions.These cutting-edge research and application has also led to new and higher requirements for the diagnosis of laser pulses: space-time resolution,and single-shot measurement.In this paper,two kinds of reconstruction algorithms are studied for ultrashort pulse diagnosis:(1)According to the principle of dispersion scan(d-scan),the d-scan reconstruction iterative algorithm is implemented,(2)Combined with spectral interference technique,Dispersion Biased Spectral Interference(DBSI)algorithm is proposed.D-scan is a widely recognized and convenient technology for laser pulse diagnosis.It has the advantages of using a single beam of light without the need of reference light,and it is also suitable for few-cycle pulse.Combined with iterative retrieval algorithm,it can acquire the time-resolved information of ultrashort pulse.Generally,the D-scan pulse diagnosis device is expensive,and its core component is mainly the D-scan reconstruction algorithm.So it has practical application value to study this algorithm.In addition,dispersion scanning process usually requires continuous scanning of the dispersion of the pulse,and spatial information of the pulse cannot be obtained.Another DBSI algorithm proposed helps to achieve single-shot spatiotemporal measurement of ultrashort pulse.Based on the D-scan and spectral interference technique,the method measures the hologram between the pulse to be measured and its dispersion-biased copy,and we can solve out the corresponding second harmonic spectrums and the phase difference between them by fourier-transforming,shifting,windowing the hologram.Combined with the reconstruction iterative algorithm,the amplitude and phase of the pulse to be measured can be retrieved,and the spatial dimension information of the pulse along the spectrometer slit direction of the imaging spectrometer can be obtained.