Building complex network from laser beam: introducing a novel parameter for beam quality analysis
Department of Optoelectronics, University of Kerala, 695581, Trivandrum, Kerala, India
Accepted: 7 March 2022
Published online: 23 March 2022
The paper introduces a new parameter, "Degree of Fluctuation (δ)", for assessing laser beam quality incorporating the concepts of graph theory for the first time in the literature. Here, a complex network is built from the beam cross-sectional eccentricity time series of a Q-switched Nd-YAG laser. Unlike the existing parameters for laser beam quality analysis, δ accounts for temporal quality. The value of δ denotes the probability distribution in the co-occurrence matrix of the mapped number vector, obtained by assigning ordinal numbers of the segments to the data points in the time series of beam cross-sectional eccentricity. The δ value is standardized by constructing a complex network from a time series of constant values and additive white Gaussian noise at different signal to noise ratio. The δ value is zero for constant time series and increases with the noise level. The increase in δ with laser power indicates the increasing temporal instability of the laser beam due to fluctuations in cavity parameters. Thus, the graph theory-based parameter δ can be used for the laser beam quality analysis.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022