Figure 4.

Tuning the colour saturation. (a) Experimental reflectance of the structures of same P with varying G and D. The gap size G was varied from 100 nm to 180 nm with an increment of 20 nm within the same pixel size P of 440 nm. Increasing G effectively reduces the square size D keeping P constant. As indicated by the dashed lines the resonance Dip2 at position 3 shifts towards the resonance Dip1 at position 1, which is invariant for changing G and D within the same P. This blue shift of the resonance Dip2 resulted in the spectral narrowing of the reflection peak R_peak. The respective colours of the pallets shown in the inset of Fig. 4a confirmed the increasing colour saturation with increasing G, which in turn provides a means for tuning the colour saturation. (b) The corresponding simulated spectra of the structures show good agreement with the measured spectra.