Figure 4: Experimental demonstrations of a macroscale visible wave bender.

(a) A photograph of the wave bender sample. The size of the scale bar, 20 mm. With a 3D printed pressing mould for wave bender, we compressed the aerogel (dashed region), resulting in the designed distribution of the compression ratio and the effective refractive index for the transformation-optics (TO) wave bender. The aerogel prepared for the wave bender sample with 45° bending has the following parameters: outer radius R₀=46 mm, inner radius r₀=37 mm, and thickness t₀=5 mm. The light beams are incident on the red spot A from the right. (b) A collimated white-light beam from a solar simulator is incident and propagates along the curved wave bender, satisfying the TO design. For reference, light propagates in a straight line inside (c) a 45°-bend, and (d) a straight homogeneous aerogel chunk, without mechanical deformation. (e) The cross-sectional images and (f) intensity profiles of light beams at the output surfaces (red edges in b,c,d. (g) Various wavelength laser beams (633, 589, 523 and 473 nm) are incident and propagate along the curved wave bender, satisfying the TO design.