HIGH-POWER, CW, DIFFRACTION-LIMITED, GAALAS LASER DIODE-ARRAY IN AN EXTERNAL TALBOT CAVITY

A 20-element linear array of single transverse mode semiconductor lasers is operated in an external Talbot cavity. A total cw output power of 250 mW in a diffraction-limited far field and 29% differential efficiency is obtained with a 50% output coupler. By decreasing the output mirror reflectivity to 20%, 900 mW cw in a 1.7 times diffraction-limited radiation pattern with an increased differential efficiency of 38% is obtained. The low fill factor of the array (1:12) acts as a spatial mode-selective filter resulting in strong mode discrimination.