Beam combination of multiple vertical external cavity surface emitting lasers via volume Bragg gratings

We present an experimental study on beam combining techniques with multiple vertical external cavity surface emitting lasers (VECSELs) using volume Bragg gratings (VBGs). The specially designed holographic gratings introduce frequency specific feedback for the near infrared wavelength VECSELs to achieve both spectral linewidth narrowing and beam combination effects. For coherent addition, we obtained >3W output power with 8% slope efficiency in a coherent power scaling cavity scheme. In the multiplexed VBGs (MVBGs) wavelength beam combining compound cavity scheme, we measured >6W combined output with nearly 100% combining efficiency. Both beam combining/power scaling schemes produced spectrally narrowed and near diffraction limited outputs.