Frequency narrowing of a 25 W broad area diode laser

We report on the spectral narrowing of a high powered (25 W) broad area diode laser using an external cavity with a holographic diffraction grating. In a Littman–Metcalf configuration, the external cavity is able to reduce the linewidth of the diode laser to primarily a single longitudinal mode (1.8 MHz) for output powers of $≤10W$ at 852 nm. Many physics applications could benefit from such high powered, narrow linewidth lasers; however both the frequency stability and the spatial profile of the output beam show room for improvement.