Implementation and Evaluation of Data Analysis Strategies for Time-Resolved Optical Spectroscopy

Abstract

Time-resolved optical spectroscopy plays a key role in illuminating the mechanisms of many fundamental processes in physics, chemistry, and biology. However, to extract the essential information from the highly complex time-resolved data, advanced data analysis techniques are required. Here we present the implementation strategies and the evaluation of the familiar global lifetime and target analysis as well as the not so widely adopted lifetime distribution analysis (LDA). Furthermore, we demonstrate the implementation of analysis strategies dealing with a number of artifacts inherently present in data from ultrafast optical experiments. The focus of the work is placed on LDA as it allows invaluable exploration depth of the kinetic information contained in the experimental data. We establish a clear regularization procedure for the use of LDA in ultrafast optical spectroscopy and evaluate the performance of a number of factors that play a role in the reliable reconstruction of lifetime distributions. Our results show that the optimal regularization factor can be determined well with the L-curve and the generalized cross-validation techniques. Moreover, the performance evaluations indicate that the most efficient regularization norm is the identity matrix. The analytical procedures described in this work can be readily implemented and used for the analysis of any time-resolved data.

PyLDM - An open source package for lifetime density analysis of time-resolved spectroscopic data

“…Yet despite these advantages, and extensive use of the technique by the Holzwarth group [9–14], widespread adoption has been limited to date (e.g. [15–17]). We believe this to be due to the unavailability of tools performing this type of analysis.…”

“…We believe this to be due to the unavailability of tools performing this type of analysis. The OPTIMUS program [17] recently released a module facilitating this type of analysis; however, the code remains closed-source.…”

Reversible Photomodulation of Electronic Communication in a π‐Conjugated Photoswitch‐Fluorophore Molecular Dyad

“…In ag loball ifetime analysis, [36] four time constants were necessary to describe the obtained data satisfactorily.T he first decay with t 1 = 180 fs was required to describeafast process immediately following photoexcitation. Thisp rocess lies within the time resolution of the experiment (ca.…”

Influence of Arrestin on the Photodecay of Bovine Rhodopsin

“…To visualize and quantify differences in the kinetics of these intermediates with and without Tr, a global lifetime analysis (GLA) [48,49] was performed on the transient absorption data I ( λ, t ) (see SI). The GLA provided the lifetimes of meta II (1–2 min) and meta III (6–7 min) decay (Figure S3) and also suggested an increased meta III formation in presence of Tr.…”

“…[49] With this method the pre-exponential amplitudes of the sum of a large number (typically ~100) of exponential functions with fixed lifetimes (τ) were determined,…”