Optimizing the efficiency in high order harmonic generation optimization by two-color fields

We address the problem of the optimization of high-order harmonic generatio n by two laser fields of frequencies omega (0) and 2 omega (0) respectively , through a theoretical approach. The parameters that are investigated are the two lasers intensities: as well as the relative phase between the two f ields. We show that a moderate. but significant increase of efficiency can be achieved in that context and give the domain of optimized parameters. Mo reover, we quantitatively investigate the gain and set the limitation of th e optimization using such coherent control methods.