[OPTICAL REVIEW Vol. 19, No. 5 (2012) 328-331]
© 2012 The Japan Society of Applied Physics

Quality Factor of Circular Laser Diode Beam Tailored by Optical Interference

Takehiro FUKUSHIMA, Koichiro SAKAGUCHI, and Yasunori TOKUDA

Department of Information and Communication Engineering, Okayama Prefectural University, Soja, Okayama 719-1197, Japan

(Received March 21, 2012; Accepted July 23, 2012)

The quality factor of a laser diode beam tailored by Lloyd's mirror interference was investigated numerically and experimentally. The far and near-field patterns were analyzed by numerical calculations based on Huygens' integral. An almost circular tailored beam was calculated to have a quality factor as low as 1.08. This beam-shaping technique was experimentally demonstrated using a commercial 640 nm laser diode and a mirror-polished GaAs substrate. The optical beam tailored by Lloyd's mirror interference was nearly circular and its beam quality factor was measured to be 1.24. Although this measured beam quality factor is slightly higher than the numerically calculated one, it is acceptably low.

Key words: laser diode, beam shaping, beam quality factor, Lloyd's mirror interference