Ultrafast exciton dynamics reconstruction with a ptychographic approach

Gian Luca Dolso,Bruno Moio,Matteo Lucchini,Rocío Borrego-Varillas,Mauro Nisoli,Nicola Di Palo,Giacomo Inzani,C Sibilia,A Belardini,G Pauliat

doi:10.1051/epjconf/202125513005

Abstract

Excitons characterize the ultrafast response of many materials of technological interest. While the development of attosecond science has unlocked the possibility of performing experiments with a suitable timeresolution, the access to the exciton properties remains a non-trivial step. We propose therefore a novel approach to disclose the physical properties behind the ultrafast exciton dynamics based on a phase-retrieval method.

Highlights

Excitons are at the basis of several technological applications in the field of electronics and optoelectronics [1], and their relevance for future devices is expected to grow
Attosecond transient absorption and reflection spectroscopies have allowed for the study of ultrafast exciton and electron dynamics in solid-state materials [2,3,4]
We have verified that our method is more accurate when compared to an ordinary non-linear fitting procedure, and requires fewer a priori information on the exciton dynamics, since ePIX makes no assumption regarding the dipole O(t)

Summary

Introduction

Excitons are at the basis of several technological applications in the field of electronics and optoelectronics [1], and their relevance for future devices is expected to grow. The thorough study of their physical properties and optical response is, a necessary endeavor to achieve their active (optical) control. In this context, attosecond transient absorption and reflection spectroscopies have allowed for the study of ultrafast exciton and electron dynamics in solid-state materials [2,3,4]. The direct extraction of the relevant parameters governing the excitonic response, such as the lifetime and the phonon coupling strength, is a non-trivial procedure and often requires a priori assumptions. We propose a novel method to achieve this goal: ePIX (the extended Ptychographic Iterative engine for eXcitons), based on an iterative ptychographic approach [5]

Methods

Results

Conclusion