Generating high-energy densities by sidelobe suppression in the far-field of phase-locked lasers

Abstract

Laser beams with high-energy densities are desired for both fundamental research and applied applications. We present a numerical study on the generation of high-energy densities by sidelobe suppression in the far-field intensity distribution of phase-locked lasers. The method relies on modifying the combined field distribution of phase-locked lasers to obtain uniform amplitude and phase distributions in a near-field plane, which enables the formation of a high-energy density main central lobe (zeroth order) in the far field. The method is applied to various one-dimensional (1D) and two-dimensional (2D) array geometries, such as square, triangular, Kagome, random, and 1D ring. The results show that for in-phase-locked lasers in 2D array geometries, the diffraction efficiency of the high-energy density region (zeroth-order lobe) can be increased in the range of 90%–95%. For in-phase-locked lasers in a 1D ring array, the maximum diffraction is found to be ∼ 75 % . Further, the effects of the range of phase locking, system size, as well as topological defects are examined on diffraction efficiency. The method is also applied to an out-of-phase-locked laser in the square array, and a high-energy density output beam is obtained.