Analysis of partially coherent combining of 2D arrays of laser beams

Jan K. Jabczynski; Przemysław Gontar

doi:10.1117/12.2324986

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9 October 2018 Analysis of partially coherent combining of 2D arrays of laser beams

Jan K. Jabczynski, Przemysław Gontar

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Proceedings Volume 10798, High-Power Lasers: Technology and Systems, Platforms, and Effects II; 107980A (2018) https://doi.org/10.1117/12.2324986
Event: SPIE Security + Defence, 2018, Berlin, Germany

Abstract

The semi-analytical model for evaluation of partial coherent combining of 2D laser beams was developed. The 2D arrays of laser beams ordered in rectangular or hexagonal lattice architecture were analyzed. The far field intensity distributions were calculated based on partial coherent summation of individual Fourier images. The partial coherence coefficients matrix based on the geometry of the array and Gaussian-Schell coherence function with a priori defined coherence radius was implemented. To define metrics of combining efficiency, Power In Bucket (PIB) distributions were calculated for each case. The more dense hexagonal geometry has shown the advantages over rectangular one, mainly because of better filling factor. The two opposite cases (fully coherent combing vs incoherent combining) were analyzed in the first steps. It was found that taking the criterion of 86.5% of PIB we obtained the same beam diameter in both cases for rectangular geometry. In a case of hexagonal geometry more than 2x beam area in far field was obtained for the incoherent combining w.r.t coherent combining for ‘top-hat’ beam evidencing the important role of the compactation and beam profile shaping. The worst case of profile is the untruncated Gaussian one for which the power content in main diffraction lobe is below 40% and more than 60% bigger beam area at 86.5% PIB comparing to ‘top-hat’ beam array with the same lattice architecture.

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Jan K. Jabczynski and Przemysław Gontar "Analysis of partially coherent combining of 2D arrays of laser beams", Proc. SPIE 10798, High-Power Lasers: Technology and Systems, Platforms, and Effects II, 107980A (9 October 2018); https://doi.org/10.1117/12.2324986

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