title: Coherent beam combining of high power broad-area laser diode array with a closed-V-shape external Talbot cavity.
abstract: We have coherently combined a high-power broad-area laser diode array by using a feedback loop closed off-axis external Talbot cavity. The off-axis feedback from two gratings provides transverse-mode control of broad-area lasers. The Talbot configuration of the external cavity implements diffractive coupling among laser diodes. Feedback from two gratings increases external cavity quality factor and spectrum selection capability. As a result, spatial coherence was improved and spectral linewidth was narrowed down. The high visibility of the far-field profile indicates that high spatial coherence was achieved. We also observed symmetric far-field profiles indicating that laser array was phase locked to in-phase and out-of-phase super-modes, respectively. Transition between these super-modes was observed by tuning one grating's tilted angle.
authors.affiliation: Center for Engineering Science Advanced Research, Computer Sciences & Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA. liub@ornl.gov
authors.forename: B
authors.initials: B
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Braiman