A high energy semiconductor laser capable of high optical efficiency includes a master oscillator coupled to a plurality of slave oscillators, each producing a laser beam that is substantially at the same wavelength as the output beam from the master oscillator. The CCEs may be arranged in levels where a first level aggregates less CCEs than a second level. The edge control system comprises first and second annular ribs, each of which comprises a first end portion sealingly coupled to the carrier head housing, a second end portion coupled to the diaphragm, and a strain relief member substantially intermediate the first end portion and the second end portion.