Fig. 1. Output spectra of 2 kW narrow linewidth fiber lasers based on oscillator cavity seed source with significant SRS

Fig. 2. Principle of thermal blooming effect without wind

Fig. 3. Transmission curve of 1--1.2 μm laser through H₂O in atmosphere

Fig. 4. Experimental setup of thermal blooming in an SBC system

Fig. 5. Distributions of far-field beam pattern. (a)--(c) Distributions of far-field beam pattern of the 1064, 1072, and 1084 nm laser beams when the sub-beam output power is 1400 W and 1800 W, respectively; (d) distributions of far-field beam pattern when the power of three-channel combined beam is 2000 W and 3800 W , respectively

Fig. 6. Distributions of far-field beam pattern when the 1084 nm laser output power is increased from 1400 W to 1800 W, under different optical path lengths. (a)100 mm;(b)150 mm;(c)260 mm;(d)450 mm

Fig. 7. Distributions of far-field beam pattern of 1084 nm laser at 1400 W and 1800 W output power after N₂ injection