ABSTRACT

Anti-reflection (AR) is a natural phenomenon that reduces the optical reflectivity. AR coatings on the optical surfaces not only reduce the unwanted loss due to reflection, but also improve the light-harvesting efficiency in solar cells or photodetectors, or maximise the optical transmission enhancing the image clarity in display devices. Researchers have now learned from nature to mimic the sub-wavelength or gradient-index AR structures observed in moth’s eyes, reducing even over 99% of reflectance in visible (VIS) spectral region. Efforts are currently on to achieve broader bands of AR regime, with omnidirectional and polarisation independency. This review presents selected state-of-the-art AR techniques, and

their guiding principles, to predict a logical trend for future research in this field.