Harnessing Multimode Broad-Area Laser-Diode Emission Into a Single-Lobe Diffraction- Limited Spot

A spectrally resolved phase manipulation technique external to the laser cavity is used to reshape the multimode emission of a conventional broad-area laser diode into a diffraction-limited single-lobe spot. A mode conversion efficiency of 60% with a total insertion loss of 25% has been demonstrated with conventional optical elements and a binary phase mask.