The team of scientists from the Institute of Physics was awarded the 1st place at the international conference Nanocon 2016 for the best poster on the topic Top-down and bottom-up fabrication of polycrystalline diamond-based photonic crystals. The competition consisted of more than 220 posters from the Czech Republic and abroad. The awarded poster was presented by Dr. Marián Varga from the Department of Optical Materials of the Institute of Physics of the CAS. The presented work dealt with the fabrication of two-dimensional polycrystalline diamond-based photonic crystals (PhC) by two different approaches and study of their optical properties in a close collaboration with the Department of Thin Films and Nanostructures (Dr. Lukáš Ondič). In the first case the PhCs were fabricated by the plasma dry etching of the fully-closed diamond film through the mask made by electron beam lithography. Second approach was based on the direct diamond growth on patterned quartz substrates. In both cases an effective coupling/out-coupling of the light at desired wavelengths was achieved. The optimization of individual technological steps led to a preparation of photonic structures of required dimensions which allowed for instance, 14 times higher out-coupling efficiency of the photoluminescence from incorporated optically active silicon-based colour centres. Such diamond-based PhCs are suitable for realization of an extremely sensitive bio-sensor devices.