High-brightness output from a laser-diode array coupled to a phase-conjugating mirror

We obtain single-lobed, near-diffraction-limited output from a 20-element laser-diode array coupled to an apertured photorefractive phase conjugator. At low driving currents the output beam is diffraction limited and contains 75% of the total output power emanating from the array. At high driving current a 1.5× diffraction-limited lobe contains 490 mW of power, or 54% of the output power. By studying the near-field emission pattern and the frequency spectrum of the laser, we confirm that the apertured conjugator selects a narrow range of output array transverse modes.