Education of the republic of uzbekistan tashkent state technical university named after islam karimov

 
CONCLUSION. 
Thus, in this work, we numerically investigated the process of optical 
parametric amplification of short laser pulses in crystals with a regular domain structure of 5% 
MgO: LiNbO3. The process is investigated under nonstationarity and self-action conditions. 
The calculations were carried out for the duration of the main pulse

100, 

50 and

20 fs with 
intensity
16
2
3
10
/
I
W m

., that is, in those conditions under which the effects of dispersion and 
cubic nonlinearity of the Kerr type begin to affect. 
A numerical OPA experiment was carried out to identify the effects that impede 
obtaining an effective OPA. Calculations have shown that the effect of the dispersion of the 
medium increases with decreasing pump pulse duration. In addition, as the intensity increases, 

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Technical science and innovation
180 
the effect of the third-order susceptibility is enhanced, which leads to a change in the refractive 
index of the medium. From this point of view, to obtain a highly efficient OPA, it is necessary 
to take into account the levels of intensity and duration of the main pulse in accordance with 
the obtained experimental conditions. 
Numerical investigation was carried out for the following realistic case: the pump, 
signal and idler wave wavelengths
1
3, 4
m



, 
3
1,064
m



and 
2
1,5486
m



, 
correspondingly. While pulse durations of the pump and signal waves were chosen for three 
different cases:
100
fs


,
50
fs


and
20
fs


. It was shown that signal wave efficiency is 
increased despite of the influences of the Kerr nonlinearities and dispersions of the nonlinear 
lattice. Maximum efficiency conversion of the signal wave were calculated 25 %, 18% and 3 
% for pulse durations
100
fs


,
50
fs


and, 
20
fs


correspondingly.
This work was partially supported by the grants UZB-Ind-2021-96 UZB-Ind-2021-83 
and of the Ministry of Innovative Development of the Republic of Uzbekistan