Coherent two-dimensional spectroscopy of a Fano model

TL;DR

This paper presents a detailed theoretical analysis of Fano resonance lineshapes using two-dimensional electronic spectroscopy, revealing new insights into the system parameters and dynamics of Fano models.

Contribution

It provides a full time-dependent response solution for a Fano model in 2DES, enabling extraction of new system parameters and deeper understanding of Fano interference.

Findings

Derived the complete third-order response of a Fano system in 2DES.

Identified new system parameters accessible through 2DES.

Enhanced understanding of Fano interference in complex systems.

Abstract

The Fano lineshape arises from the interference of two excitation pathways to reach a continuum. Its generality has resulted in a tremendous success in explaining the lineshapes of many one-dimensional spectroscopies - absorption, emission, scattering, conductance, photofragmentation - applied to very varied systems - atoms, molecules, semiconductors and metals. Unravelling a spectroscopy into a second dimension reveals the relationship between states in addition to decongesting the spectra. Femtosecond-resolved two-dimensional electronic spectroscopy (2DES) is a four-wave mixing technique that measures the time-evolution of the populations, and coherences of excited states. It has been applied extensively to the dynamics of photosynthetic units, and more recently to materials with extended band-structures. In this letter, we solve the full time-dependent third-order response, measured in 2DES, of a Fano model and give the new system parameters that become accessible.