Control of the spatiotemporal emission of a broad-area semiconductor laser by spatially filtered feedback.

We demonstrate the control of the spatiotemporal emission dynamics of a broad-area semiconductor laser in an external optical feedback configuration formed by a spatially filtering mirror. The emission properties are studied with a single-shot streak camera with temporal resolution of approximately 7 ps and spatial resolution of approximately 5 microm. Our results show a significant reduction of the spatial filamentation and, furthermore, suppression of the spatiotemporal instabilities, which are both intrinsic emission properties of standard high-power broad-area lasers. Associated with the control of the emission dynamics, strong improvement of the beam quality, which is essential for numerous high-power applications, is possible.