Fig. 6

Schematic illustration of fabrication procedure. a Overall workflow of the fabrication. The sample undergoes steps of spin-coating BY solutions, photoalignment exposure and humidity treatment, inkjet printing LC mixture, heating and UV polymerization. b Diagram of exposure interferometer setup. The laser light, after filtering and expansion, is modulated by a HWP and split by a PBS into two beams. Each beam is modulated by a QWP, reflected by a mirror, and expanded by a 3 × beam expander, before being modulated by the freeform surface (recording beam) or directly reaching the sample (reference beam)