Periodically alternated metallic/dielectric nanocomposites and dielectric films for the fabrication of high-efficiency Bragg reflectors: a case study

A 183 nm periodic structure including four pairs of Au NPs/SiO2 nanocomposites and SiO2 films was fabricated by repeatedly implanting Au ions into the SiO2 film produced by the radio-frequency magnetron sputtering. Our results reveal that the fabricated periodic structure, although its refractive index variation is only 0.26, can reach a peak reflectivity of 70% at a wavelength of about 550.0 nm. Besides, the peak reflectivity of such structure has been found to be nearly proportional to the number of nanocomposite layers. Our findings could be very helpful to construct small-sized but high-efficiency Bragg reflectors in the large-scale photonic integrated circuits.