Spatially modulated broad-area lasers for narrow lateral far-field divergence.

A novel laser design is presented that combines a longitudinal-lateral gain-loss modulation with an additional phase tailoring achieved by etching rectangular trenches. At 100 A pulsed operation, simulations predict a far-field profile with 0.3° full width at half maximum (Θ F W H M =0.3 ∘ ) where a 0.4°-wide main lobe contains 40% of the emitted optical output power (Θ 40% =0.4 ∘ ). While far-field measurements of these structured lasers emitting 10 ns long pulses with 35 W peak power confirm a substantial enhancement of radiation within the central 1∘ angular range, the measured far-field intensity outside of the obtained central peak remains high.