Fig. 1. Principle and applications of focusing through turbid medium based on wavefront shaping technique

Fig. 2. Schematic diagrams of iterative optimization algorithms^[29]. (a) Stepwise sequential algorithm; (b) continuous sequential algorithm; (c) partitioning algorithm

Fig. 3. Schematic diagrams of intelligent optimization algorithms. (a) Genetic algorithm^[30]; (b) bat algorithm^[31]; (c) simulated annealing algorithm^[32]; (d) particle swarm optimization algorithm^[33]; (e) separable natural evolution strategies^[34]

Fig. 4. Schematic and focusing results of machine learning algorithms. (a) Support vector regression^[38]; (b) single-layer neural network and convolutional neural network^[39]; (c) multi-plane neural network^[40]

Fig. 5. Principles and focusing results of hybrid optimization algorithms. (a) Combination of DCNN and GA^[41]; (b) combination of SLNN and PSO^[42]

Fig. 6. Iterative optimization system dependent on fluorescence excitation with different feedback signals. (a) Fluorescence intensity^[45]; (b) fluorescence intensity variance^[46]

Fig. 7. Iterative optimization system using photoacoustic signals as feedback. (a) Schematic diagram of iterative optimization for optical focusing assisted by photoacoustics^[27]; (b) schematic diagram of photoacoustic detection based on non-uniform detection sensitivity^[47]; (c) schematic diagram of iterative optimization based on nonlinear photoacoustics^[20]; (d) schematic diagram of nonlinear photoacoustics based on Grüneisen relaxation^[48]

Fig. 8. Focusing through turbid medium based on transmission matrix method^[70]. (a) Experimental setup; (b) focusing results

Fig. 9. Transmission matrix controlling different physical quantities. (a) Polarization transmission matrix^[72]; (b) photoacoustic transmission matrix^[73]

Fig. 10. Applications of multispectral transmission matrix. (a) Optical focusing^[74]; (b) time-domain shaping^[75]

Fig. 11. Applications of OAM based transmission matrix. (a) Focusing through scattering medium^[76]; (b) data transmission^[77]

Fig. 12. Applications of transmission eigenchannels. (a) Ultrasound-assisted optical focusing^[83]; (b) glare suppression^[64]; (c) energy delivery to specified depth^[65]

Fig. 13. Applications of transmission matrix. (a) Pulse width compression^[84]; (b) OAM optical communication^[10], (c) multimode fiber optical communication^[85]; (d) aberration correction^[86]; (e) particle manipulation^[18]

Fig. 14. OPC technologies with different principles. (a), (b) OPC technology based on photorefractive effect^[91-92]; (c), (d) digital OPC technology^[93-94]

Fig. 15. Applications of DOPC system guided by magnetic particle. (a) Focusing inside turbid medium^[98]; (b) dynamic light focusing^[99]

Fig. 16. TRUE method applied to different systems. (a) OPC system^[100]; (b) DOPC system^[101]