Isolated sub-30-attosecond pulse generation using a multicycle two-color chirped laser and a static electric field

Abstract

We present a theoretical investigation of high-order harmonic generation in a chirped two-color laser field, which is synthesized by a 10-fs/800-nm fundamental chirped pulse and a 10-fs/1760-nm subharmonic pulse. It is shown that a supercontinuum can be produced using the multicycle two-color chirped field. However, the supercontinuum reveals a strong modulation structure, which is not good for the generation of an isolated attosecond pulse. By adding a static electric field to the multicycle two-color chirped field, not only the harmonic cutoff is extended remarkably, but also the quantum paths of the high-order harmonic generation (HHG) are modified significantly. As a result, both the extension of the supercontinuum and the selection of a single quantum path are achieved, producing an isolated 23-as pulse with a bandwidth of about 170.6 eV. Furthermore, the influences of the laser intensities on the supercontinuum and isolated attosecond pulse generation are investigated.

Isolated attosecond pulse generation with few-cycle two-color counter-rotating circularly polarized laser pulses

“…[1][2][3][4] Many schemes for generating IAP have been proposed and investigated. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] However, most of them are sensitive to the carrier-envelope phase (CEP) of the driving laser pulses. [23,24] From the viewpoint of experiments, almost all laser systems cannot maintain the stability of CEP in the long term.…”

“…[34][35][36][37][38] Some research on HHG has also been conducted using few-cycle MIR laser pulses. [8,22,23,[39][40][41][42][43] In this work, we further theoretically study the IAP generation using few-cycle TC-CRCP laser pulses and investigate the dependence of IAP on CEP of the driving laser pulses, finding that IAP can be generated at most of CEPs, although at some CEP, the intensity of IAP is weaker. The CEP dependence of the IAP generation is much reduced, which thus reduces the requirements for the lasers in experiments.…”