Fig. 1. Design schematic of free-form beam splitter

Fig. 2. Schematic of subarea division of incident beam

Fig. 3. Schematic of ray map from subarea B_n,m to corresponding spot area Ω_n,m

Fig. 4. Schematic of relationships between freeform surface data points and normal vectors

Fig. 5. Model of FBS 1 and ray tracing illustration

Fig. 6. Ray tracing simulation results of FBS 1. (a) 2D spot array; central irradiance profiles of (b) 5^th column and (c) 1^st row

Fig. 7. Physical optical simulation results of FBS 1. Simulated spot of A_3,3 (a) true color, (b) false color; simulated spot of A_1,1 (c) true color, (d) false color

Fig. 8. FBS 2 model, ray tracing and energy scale diagram. (a) Model of FBS 2 and ray tracing illustration; (b) predefined energy proportion of target spot array

Fig. 9. Ray tracing simulation results of FBS 2. (a) 2D spot array; central irradiance profiles of (b) 1^st, (c) 2^nd, (d) 3^rd, (e) 4^th, and (f) 5^th column

Fig. 10. Physical optical simulation results of FBS 2. Simulated spot of A_3,3 (a) true color, (b) false color; simulated spot of A_1,1 (c) true color, (d) false color

Fig. 11. Edge profiles and sag mutation curves of sub-surfaces of FBS 1. (a) A₁ and A₅; (b) A₂ and A₄; (c) A₃; (d) sag mutation curves between adjacent sub-surfaces

Fig. 12. Edge profiles and sag mutation curves of sub-surfaces of FBS 2. (a) A₁; (b) A₂; (c) A₃; (d) A₄; (e) A₅; (f) sag mutation curves between adjacent sub-surfaces