Figure 6.

Different THz diffractive optical structures manufactured using: (a) laser cutting to manufacture hyperbolic lens [9] from paper, (b) extrusion-based 3D printing to make a mold to form converging lens from paraffin, (c) extrusion-based 3D printing from PA12 for off-axis focusing lens, (d) selective laser sintering (powder-based 3D printing) from PA12 to manufacture point-to-point redirecting lens and (e) ablation in silicone to fabricate Fibonacci lens (photograph courtesy Linas Minkevičius, FTMC, Vilnius).