Fig. 1. Change curves of correlation coefficient with number of focal points

Fig. 2. Simulated focus effect. (a) Multi focal points; (b) letter mask

Fig. 3. GSW algorithm principle

Fig. 4. Simulated results of focusing. (a) Phase conjugation method; (b) MSO; (c) GSW algorithm

Fig. 5. Variation curve of correlation coefficient of simulation results based on the GSW algorithm with number of iterations

Fig. 6. Schematic of experimental setup for measuring transmission matrix

Fig. 7. Experimental results of the single- and multi-point focusing. (a) Single focal point; (b) 25 focal points; (c) 100 focal points

Fig. 8. Change curves of correlation coefficient with number of focal points

Fig. 9. Experimental results of the GSW algorithm focusing on letter masks. (a) “T”; (b) “N”; (c) “J”

Fig. 10. Experimental results of focusing on the letter mask “H”. (a) Phase conjugation; (b) MSO; (c) GSW algorithm