Phase Difference Effect On High-order Harmonic Generation Of Crystals Driven By Two-color Laser Pulses

High-order harmonic generation(HHG)is a kind of no-liner effect under the process of intense laser interaction with matter such as atoms,molecules and solids.Due to its special structural characteristics,it is used in various disciplines and social sectors.Under the action of external strong laser field,the high order harmonic spectrum of the crystal is different from the that emission by atomic and molecular and presents the characteristics of dual platform structure.After a lot of theoretical experiments,it is found that the first platform of crystal harmonics is dominated by two part,one is the electronic transition between the lowest conduction band and the valence band,and another is the inner band buloch oscillation.In this paper,in the frame of semi-classical theory,a one-dimensional time-dependent schrodinger equation of two-color laser field interaction with crystal is solved numerically.In this condition,the harmonic structure of crystal emission has not changed,and still present a dual platform.The yield of the first platform does not vary greatly with the phase difference of two-color laser fields,but the yield of the second platform is significantly higher than that of the monochrome field.Besides,it change greatly with different phase difference,which also the main research topic of this paper.Therefore,according to the nature of HHG second platform yield emitted by crystal changes with the relationship between phase difference,we can put forward a new method of measuring two color laser pulse phase difference,also can use this to improve the strength of the second platform of the crystal harmonics.