Isolated sub-100-as pulse generation by optimizing two-color laser fields using simulated annealing algorithm.

We propose a method to broaden the cut-off region of high harmonic generation by optimizing the parameters of two-color laser fields synthesized by an intense 5 fs pulse at 800 nm and a relatively weak, subharmonic pulse at 2400 nm. Simulated Annealing (SA) algorithm is employed to optimize the electric field amplitude, pulse duration of the control pulse, and the time delay between two pulses. Our simulation shows that a broadened XUV supercontinuum with a 115 eV spectral width can be generated, which is two times broader compared with no optimization, and directly creates an isolated 76as pulse even without any phase compensation.