Attosecond pulse synthesis from high-order harmonic generation in intense squeezed light

TL;DR

This paper demonstrates that using intense squeezed light in high-order harmonic generation enables phase-locking of the entire harmonic spectrum, significantly reducing attosecond pulse duration and providing a new method for generating ultra-short pulses.

Contribution

It introduces a theoretical framework showing that squeezed light can produce phase-locked harmonics across the entire HHG spectrum, independent of the target system.

Findings

Harmonics in the entire spectrum can be phase-locked using squeezed light.

The width of the synthesized attosecond pulse depends on the squeezing parameter.

The phase-locking mechanism is target-independent.

Abstract

High-order harmonic generation (HHG) provides a broad spectral bandwidth for synthesizing attosecond pulses. However, in the current HHG schemes, only part of the harmonics can be phase-locked, which limits the ability to achieve shorter attosecond pulses. Here, we study attosecond pulse synthesis from HHG of an atom driven by an intense quantum light, i.e., squeezed light. It is interestingly found that the harmonics in the whole spectrum can be phase-locked and, by using these harmonics, the width of the synthesized attosecond pulse is greatly reduced. By developing strong-field approximation theory in squeezed light, the physics of the phase-locked harmonic generation throughout the HHG spectrum is revealed and is found to be independent of the target system. Furthermore, we uncover the dependence of the synthesized attosecond pulse width on the squeezing parameter of the squeezed light. Our findings provide a robust tool for obtaining phase-locked harmonics throughout the HHG spectrum for synthesizing short attosecond pulses.