Document Type : Original Article
Authors
1
Department of Photonics, Faculty and Research Institute of Basic Science, Imam Hussein Comprehensive University, Tehran, Iran
2
Department of Photonics, Faculty of Basic Science, Imam Hussein University, Tehran, Iran
Abstract
The performance of a laser system based on coherent beam combination (CBC) is evaluated by combined beam quality metrics. In this article, the comparison and analysis of these combined beam quality metrics, in the coherent combination of Gaussian beams, is presented. These metrics include M2 factor, Strehl ratio (SR), power and average intensity in the diffraction limited bucket (PIBdl and Idl), power in the bucket of 5 cm (PIB5cm) and 20 cm (PIB20cm). In this regard, arranys with hexagonal, ring, square and rectangular geometry have been used. Also, factors such as the waist radius of beams, separation distance among adjacent beams and the number of elements have been investigated and studied. The simulation results show that in all arrays, the beam quality increases by increasing the waist radius of beams and decreasing the distance between them. Also, with the increase in the number of elements, the power in the diffraction limited bucket and the Strehl ratio tend towards constant values; However, the M2 factor metric is associated with a decrease in the quality of the combined beam and the Idl, PIB5cm and PIB20cm metrics are associated with an increase. Although, to evaluate the quality of a single laser beam, the metric of M2 factor and Strehl ratio are used; But evaluating the combined beam quality with such metrics does not seem very proper. Therefore, in the applications that require the use of central lobe, the power in the diffraction limited bucket and in direct energy applications, the Idl, PIB5cm and PIB20cm metrics are suitable.
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