Ultrafast Insights: A Fundamental Overview of Transient Absorption Spectroscopy

Abstract
Transient Absorption Spectroscopy (TAS) offers a unique lens to observe the ultrafast processes that govern the behaviour of matter immediately after excitation. TAS provides a direct visualization of excited-state dynamics by using femtosecond pump-probe techniques, where carrier relaxation pathways, energy redistribution and charge-transfer processes can be observed over timescales previously inaccessible by standard spectroscopic techniques [1,2].
Besides, TAS allows to extract quantitative kinetic parameters, like excited-state lifetimes, diffusion coefficients, and electron-phonon coupling strengths, and thus gain profound understanding of the underlying processes that act to regulate light-matter interactions in complex materials. This presentation will provide a brief, but thorough discussion of the key concepts of TAS, the experimental configuration, issues of temporal and spectral resolution
and how transient signals may be interpreted and how TAS may transform our knowledge of ultrafast processes in chemistry, physics and materials science.

Reference
1. Crane, Stuart W., et al. "The value of different experimental observables: a transient absorption study of the ultraviolet excitation dynamics operating in nitrobenzene." The Journal of Physical Chemistry A 127.31 (2023): 6425-6436.
2. Jia, Menghui, et al. "Transient Absorption Spectroscopy: Probing the Ultrafast Dynamics in Nanomaterial Complex Systems." (2024).