Intensity Distribution Characteristics of Partially Coherent Flat-Topped Beam Combination Projected on Cavity Wall

Abstract

A model is established to study the propagation of the lens-focused laser beam combination in the hohlraum in the progress of laser indirect driving. As for all laser beams in cone rings projected on the hohlraum wall, the incoherent superposition characteristics of intensity distribution of focal spots are investigated based on the Collins formula. The effects of relative spatial coherence degree, lens focusing F number and defocusing amount on the intensity distribution uniformity of focal spots projected on the target wall are discussed in detail. As the spatial coherence degree increases, the spot intensity of incoherent superposition increases, the light intensity fluctuation becomes more apparent, and the uniformity of the top light intensity distribution deteriorates. The spot intensity also increases with the increase of focusing F number, the intensity fluctuation is more violent, and the uniformity of the top light intensity distribution deteriorates. As the defocusing amount increases, the light intensity on the target chamber surface is reduced, the volatility degree and the difference of light intensity peak are smaller while the top intensity distribution becomes more homogenous.