Fig. 3: Optical Janus effect with colour tuneability by modifying the effective RI of the dielectric layer.
From: Asymmetric optical camouflage: tuneable reflective colour accompanied by the optical Janus effect
a Calculated reflective colours of the BEE upon opposite incidences (upper and lower half seen from the frontside and backside) as a function of nsolvent and fCYTOP. b Conceptual illustration of controlling the dielectric nanomorphology by moving a mask during RIE. c, d Experimental reflective optical spectra measured from the frontside c and backside d with etching durations of 0, 20, 40, and 60 s (insets: photographs of each side). e–g Photographs of the BEE under media of n = 1.0 (air) and nsolvent = 1.3, 1.4, 1.5, and 1.6 (solvents) (e, insets show calculated colours), and their corresponding measured reflective optical spectra f, g. Scale bars, 1 cm
