Fig. 1. Schematic of solar reflection on freeform surface

Fig. 2. (a) Designed reflection surface of freeform surface based on Monge-Ampére theory; (b) structure schematic of the freeform surface reflector

Fig. 3. Schematic of the lightguide with hemisphere beam coupling structure array

Fig. 4. (a) Structure schematic of the solar concentration system; (b) ray-tracing schematic of TracePro

Fig. 5. Curves of focusing efficiency and geometric concentration ratio versus lightguide length

Fig. 6. Schematic diagram of freeform surfaces with different circumferential radii r of ?S2 boundary. (a) r=0.1 mm; (b) r=0.2 mm; (c) r=0.3 mm; (d) r=0.4 mm; (e) r=0.5 mm; (f) r=0.6 mm

Fig. 7. Influence of circumferential radius of ?S2 boundary on focusing efficiency