Polydimethylsiloxane Nano-Hemispheres Array for Color Separation

We demonstrate an array of poly(dimethylsiloxane) (PDMS) nano-hemisphere for color separation by using soft lithography techniques. Each array of a PDMS nano-hemisphere has an area of 1080 μm × 820 μm with well-defined period and diameter. The diameter of each nano-hemisphere and period between nano-hemispheres can be varied to produce the desired color. The periods and diameters are (1400, 1120), (1500, 1040), and (1600, 960) nm for red, yellow, and green colors, respectively. The reflection spectrum obtained from coupling between an incident light and the nano-hemispheres array can be utilized for fluorescence spectroscopy as filters or spectral analysis for lab-on-a-chip devices.