Scalable, thermally efficient pump diode systems. These systems may include a first substrate having a plurality of grooves in alignment with a second substrate having a plurality of grooves. A first single emitter diode laser (“emitter”) may be disposed between the first substrate and the second substrate and aligned between two of the plurality of such grooves. Additional emitters or spacers may be disposed adjacent the first emitter such that at least one groove separates the elements (emitters/spacers). The grooves, which may comprise shallow scribes, channels, and/or other isolation structures, provide electrical isolation between adjacent emitters and/or spacers. A conductive layer may be disposed between the emitter(s) and the substrate(s), in electrical contact with each emitter, to provide power for operation of the emitters. A plurality of such assemblies, in a one-dimensional or a two-dimensional configuration, may be mounted, in a parallel or serial electrical power drive arrangement, adjacent a lasing medium to improve heat removal and/or to provide more efficient excitation of the medium.