Extension of high-order harmonics and generation of an isolated attosecond pulse in the chirped laser field

Abstract

This paper theoretically investigates the high-order harmonic generation cutoff extension using intense few-cycle linearly chirped laser pulses. It shows that the cutoff of the harmonic can be extended remarkably by optimising the chirping parameters. The time-frequency characteristics of high-order harmonics with different chirping parameters are analysed by means of wavelet transform of the dipole acceleration. It also gives out the classical three-step model pictures of electron. By superposing a properly selected range of the harmonic spectrum, it obtains an isolated 65as pulse.

Generation of an isolated sub-40-as pulse using two-color laser pulses: Combined chirp effects

“…Turning to the profile of the chirped laser field shown in Fig. 2(a) (dashed red line), 053853-3 we can see that with the introduction of the chirp, albeit the intensity of the amplitude (peak C or C ) remains unchanged but the B -C -D process has been obviously broadened; therefore, the electron must take much more time in its processes of accelerating and returning to the parent ion, which is responsible for the extension of the cutoff energy [21,40,41]. Moreover, as seen in Fig.…”

Enhancing High-Order Harmonic Generation in Light Molecules by Using Chirped Pulses

“…Some of them [30,32] have already been realized in the lab, but their widespread implementation is somewhat limited due to their intrinsic complexity (use of several pulses, synchronization, preexistence of attosecond pulses, etc). Another alternative is the use of intense few-cycle chirped pulses, which have been proposed for atoms [36][37][38] and diatomic molecules [39] but with rather limited success.…”