Generation And Measurement Of Intense Few-cycle Blue Femtosecond Laser Pulses

Few-cycle intense blue femtosecond laser pulses are powerful tools due to their strong electric field,ultrabroad spectra and unprecedented ultra-short time resolution,such as improving the conversion efficiency of high-order harmonic generation,pumping the wideband gap matter and generating warm dense matter.In this work,we set up laser system that can generate high single-pulse energy??50?J?few-cycle blue femtosecond??10fs?pulse,by using the laser system with the center wavelength of 800nm,pulse width of 25fs(1s=10^-15fs).Using this experimental platform,the conductivity and electron dynamics of warm dense matter can be studied.Firstly,we studied the influence of the thickness of?-BBO crystal,the cutting angle and the incidence angle of fundamental light on the conversion efficiency of frequency doubling,which is based on the fundamental theory of femtosecond laser pulse and the principle of second harmonic generation.At present,experimental equipment in the laboratory is unable to detect laser pulses in the ultraviolet band,so we have built a self-diffractive frequency-resolved optical gate system which can accurately detect the width,spectrum and phase of the pulse.At the same time,we study to generate and optimize the spectrum of few-cycle femtosecond laser pulses with a central wavelength of 800nm.On this basis,few-cycle intense blue femtosecond laser pulses are obtained successfully by frequency doubling that are single-pulse energy of 50?J and pulse width of 10.53fs,which meet the light source conditions for studying warm dense matter.The laser pulses with this characteristic are among the leading in the world.Secondly,the Auger decay of single and double K-shell hole and hollow s-tates of Al⁴⁺–Al¹¹⁺was theoretically investigated on warm dense state,which can better understand the interaction process between strong laser and materials.Finally,applica-tion of the single pulse energy of 50?J,pulse width of 10.53fs few-cycle intense blue femtosecond laser pulse is discussed,how to produce higher single pulse energy?10²?J magnitude?of few-cycle intense blue femtosecond laser pulse system that put forward the idea simultaneously.