27-mJ and 50-ns pulses are generated at 1064 nm from a 200-um diameter, 0.06 NA core Yb-doped DC fiber amplifier. Fiber supporting ~200 transverse modes is coiled to produce mode-filtered beam with M2 = 6.5.
Relation:
Conference on Lasers and Electro-Optics (CLEO), May 16, 2004