Quantum optical signatures in strong-field laser physics: Infrared photon counting in high-order-harmonic generation

TL;DR

This paper presents an analytical quantum optical model of high harmonic generation in gases, revealing photon statistics of IR laser light and enabling new spectroscopic techniques and non-classical light sources in extreme-ultraviolet and attosecond science.

Contribution

It introduces a closed-form solution of the TDSE with a quantized laser state, uncovering quantum optical features of HHG not accessible by semi-classical theories.

Findings

Reveals quantum optical properties of HHG via photon statistics.

Provides a new method for high-resolution spectroscopy without XUV detection.

Lays groundwork for developing non-classical light sources.

Abstract

We analytically describe the strong-field light-electron interaction using a quantized coherent laser state with arbitrary photon number. We obtain a light-electron wave function which is a closed-form solution of the time-dependent Schrodinger equation (TDSE). This wave function provides information about the quantum optical features of the interaction not accessible by semi-classical theories. With this approach we can reveal the quantum optical properties of high harmonic generation (HHG) process in gases by measuring the photon statistics of the transmitted infrared (IR) laser radiation. This work can lead to novel experiments in high-resolution spectroscopy in extreme-ultraviolet (XUV) and attosecond science without the need to measure the XUV light, while it can pave the way for the development of intense non-classical light sources.