Nano-structured anti-reflective surfaces replicated by hot embossing
We developed a fabrication technique of anti-reflective structures for applications in the visible spectral range. The depth and duty cycle of the grating structures optimised for wavelengths around 500 nm were calculated using rigorous diffraction theory. We used electron-beam lithography for the manufacturing of linear and crossed grating patterns with pitches of 200 nm and various duty cycles over areas of several square millimeters. The structures are transferred to a quartz master, which is then replicated by Ni electroforming into a stamper for the hot embossing into polycarbonate (PC) sheets. The optical properties of the replicated PC gratings were measured over a wide wavelength range. The general shapes of the curves are in good agreement with the calculations, and for both polarizations, the reflectivity has been reduced significantly.
anti-reflective surfaces hot embossing electron-beam lithography nanoreplication