An optoelectronic apparatus includes a heat sink, which is shaped to define a base, a first platform at a first elevation above the base, and a second platform alongside the first platform at a second elevation above the base, which is different from the first elevation. A first monolithic emitter array is mounted on the first platform and is configured to emit first optical beams. A second monolithic emitter array is mounted on the second platform and is configured to emit second optical beams. An optical element is configured to direct both the first and the second optical beams toward a target region.