For the bandwidth of 1.11 nm and the incident fundamental intensity between 3 GW/cm~2 and 8 GW/cm~2, the third harmonic conversion efficiency is 60%～70%, which has increased 30%～40% compared with that using the scheme of one doubler and one mixer.

For the incident fundamental field with the bandwidth of 11.2 nm and the intensity of 2～6 GW/cm~2,the third harmonic conversion efficiency of about 60 % can be achieved,which has increased about 40 % compared with the case without ASD method.

The results show that using the scheme of cascade crystals can improve the third harmonic conversion efficiency and increase the dynamic range of the broadband laser tripling.

It found that this design can increase the third harmonic conversion efficiency of broad bandwidth,but the distance between two triplers has an important impact on the third harmonic conversion efficiency in the experiment.

As for the temporal phase modulated broadband laser, by using some numerical techniques such as split-step Fourier transformation and fourth-order Runge-Kutta method, the effect of the intensity and bandwidth of the incident fundamental field, as well as that of the lengths of the KDP crystals on the third harmonic conversion efficiency of broadband laser have been discussed. The parameters of the mixers for the scheme of one type I doubler, one type II mixer and one type I mixer in quadrature have been...

As for the temporal phase modulated broadband laser, by using some numerical techniques such as split-step Fourier transformation and fourth-order Runge-Kutta method, the effect of the intensity and bandwidth of the incident fundamental field, as well as that of the lengths of the KDP crystals on the third harmonic conversion efficiency of broadband laser have been discussed. The parameters of the mixers for the scheme of one type I doubler, one type II mixer and one type I mixer in quadrature have been optimized. The results show that using the scheme of cascade crystals can improve the third harmonic conversion efficiency and increase the dynamic range of the broadband laser tripling. For the bandwidth of 1.11 nm and the incident fundamental intensity between 3 GW/cm~2 and 8 GW/cm~2, the third harmonic conversion efficiency is 60%～70%, which has increased 30%～40% compared with that using the scheme of one doubler and one mixer.

The dual-tripler scheme for third harmonic generation(THG) is studied by the coupled equations under the small signal and high power condition((1.5 GW/cm~2).) The design has been proved in the experiment.It found that this design can increase the third harmonic conversion efficiency of broad bandwidth,but the distance between two triplers has an important impact on the third harmonic conversion efficiency in the experiment.(19.75%) THG efficiency with chirp pulse of(3.5 nm) bandwidth at average...

The dual-tripler scheme for third harmonic generation(THG) is studied by the coupled equations under the small signal and high power condition((1.5 GW/cm~2).) The design has been proved in the experiment.It found that this design can increase the third harmonic conversion efficiency of broad bandwidth,but the distance between two triplers has an important impact on the third harmonic conversion efficiency in the experiment.(19.75%) THG efficiency with chirp pulse of(3.5 nm) bandwidth at average power of (1.5 GW/cm~2) was achieved at(25 mm) optimum distance between two triples in the experiment.It will be useful to solving the problem of the large bandwidth of the THG in the high power laser system.

Third harmonic generation(THG)of super intense femtosecond laser pulse with one BBO crystal was analyzed.Effects of the third-order and the cascaded second-order nonlinearity in one crystal on the third harmonic conversion efficiency were compared.Influences of the factors,such as input fundamental intensity,length of the crystal,self-phase-modulation (SPM) and cross-phase-modulation(XPM),group-velocity mismatching,detuned angle,azimuth angle,etc,on the conversion efficiency,pulse shape and...

Third harmonic generation(THG)of super intense femtosecond laser pulse with one BBO crystal was analyzed.Effects of the third-order and the cascaded second-order nonlinearity in one crystal on the third harmonic conversion efficiency were compared.Influences of the factors,such as input fundamental intensity,length of the crystal,self-phase-modulation (SPM) and cross-phase-modulation(XPM),group-velocity mismatching,detuned angle,azimuth angle,etc,on the conversion efficiency,pulse shape and spectra of the third harmonic field were discussed in detail.Furthermore,the methods to improve the third harmonic conversion efficiency were proposed.The results show that,the variation of the maximum intensity and the pulse width(full width at half maximum(FWHM)) of the third harmonic field with the length of the crystal is not obvious.By justifying the phase-mismatching angle of the fundamental field,the conversion efficiency and the maximum intensity of the third harmonic field can be increased,and the pulse width(FWHM) can be reduced.Moreover,it is also helpful to improvement of the conversion efficiency by optimizing the azimuth angle of the crystal.