High harmonic generation-2ω attosecond stereo-photoionization interferometry in N2

V Loriot,A Marciniak,S Nandi,G Karras,A Palacios,E Constant,M Hervé,E Plésiat,F Lépine,F Martín

doi:10.1088/2515-7647/ab7b10

Abstract

We have investigated photoionization delays in N2 by combining an extreme ultraviolet (XUV) attosecond pulse train generated by high harmonic generation (HHG) and a second harmonic femtosecond pulse with angularly resolved photoelectron spectroscopy. While photoionization delay measurements are usually performed by using a standard XUV-infrared scheme, here we show that the present approach allows us to separate electronic states that otherwise would overlap, thus avoiding the spectral congestion found in most molecules. We have found a relative delay between the X and A ionic molecular states as a function of the photon energy of up to 40 attoseconds, which is due to the presence of a shape resonance in the X channel. This approach can be applied to other small quantum systems with few active electronic states.

Highlights

31 March 2020V Loriot , A Marciniak , S Nandi , G Karras , M Herve , E Constant , E Plesiat, A Palacios , F Martın and F Lepine
Photoionization has been used as a tool for investigating quantum effects in atoms and molecules
The electron dynamics associated to these spectral features span over a broad range of timescales, which can reach the attosecond domain for broad resonances

Summary

31 March 2020

V Loriot , A Marciniak , S Nandi , G Karras , M Herve , E Constant , E Plesiat, A Palacios , F Martın and F Lepine. While photoionization delay measurements are usually performed by using a standard XUV-infrared scheme, here we show that the present approach allows us to separate electronic states that otherwise would overlap, avoiding the spectral congestion found in most molecules. We have found a relative delay between the X and A ionic molecular states as a function of the photon energy of up to 40 attoseconds, which is due to the presence of a shape resonance in the X channel. This approach can be applied to other small quantum systems with few active electronic states

Introduction

Method

Ionization to the X state of nitrogen

Conclusion