We describe effective suppression of beam divergence for a high-power laser diode bar by use of an external-cavity technique. Nineteen off-axis external-cavity laser diodes of the high-power laser diode are formed by feedback with a stripe mirror. At three times the threshold current, the diverging angle (1/<i>e</i><sup>2</sup>) of the external-cavity laser diode bar is reduced to 1.5° from 6.6° (free running) with 14.1-W peak output power and 70.4% of the radiated power of the free-running state without the external cavity. This technique effectively improves the beam quality of the high-power laser diode bar.
© 2004 Optical Society of America
(140.2010) Lasers and laser optics : Diode laser arrays
(140.3300) Lasers and laser optics : Laser beam shaping
(140.3410) Lasers and laser optics : Laser resonators
(140.5960) Lasers and laser optics : Semiconductor lasers
Xin Gao, Yujin Zheng, Hirofumi Kan, and Kazunori Shinoda, "Effective suppression of beam divergence for a high-power laser diode bar by an external-cavity technique," Opt. Lett. 29, 361-363 (2004)