K. Patokoski, J. Rissanen, T. Noronen, R. Gumenyuk, Y. Chamorovskii, V. Filippov,  J. Toivonen "Single-frequency 100 ns / 0.5 mJ laser pulses from all-fiber double clad ytterbium doped tapered fiber amplifier" Optics Express Vol. 27, Issue 22, pp. 31532-31541 (2019)