Laser diode arrays and arrays of laser diode bars are commercially available. Such arrays are fabricated typically by mounting individual laser diodes onto the top surface of a heat sink such that the emitting facet of the laser directs coherent light typically through a microlens positioned to collimate that light.
When individual laser diodes are stacked, the heat sinks are separated by a layer of electrically insulating material having a thickness equal to that of the laser diode and the insulating layer as well as the top of the laser diode are covered by a layer of electrically conducting material to which the adjacent heat sink is connected. The individual laser diodes (components) are aligned with one another in the stack such that all the emitting facets are in a single plane which is the same plane occupied by the end faces of the heat sinks.
In such arrangements, adjacent components are placed as close together as possible. But the minimum spacing, q, between adjacent components (i.e. the laser diodes or the light beams emitted thereby) is determined by the thickness of the components and the heat dissipating capacity of the stack. The best available separation between adjacent components in the stack (or array), whether the components are individual laser diodes or laser diode bars, is 1.2 mm which is capable of producing a power density of 200 watts/sq cm (cw). A characteristic of prior art stacks is that q=p.