Solar energy is regarded as one of the most plentiful sources of renewable energy. An extraordinary light-harvesting property of a germanium periodic nanopyramid array is reported in this Letter. Both our theoretical ...Solar energy is regarded as one of the most plentiful sources of renewable energy. An extraordinary light-harvesting property of a germanium periodic nanopyramid array is reported in this Letter. Both our theoretical and experimental results demonstrate that the nanopyramid array can achieve perfect broadband absorption from 500- to 800-nm wavelength. Especially in the visible regime, the experimentally measured absorption can even reach 100%. Further analyses reveal that the intrinsic antireflection effect and slow-light waveguide mode play an important role in the ultra-high absorption, which is helpful for the research and development of photovoltaic devices.展开更多
We propose and demonstrate free-space optical data links based on coaxial sidelobe-modified optical vortices（CSMOVs）. In contrast to the optical communication systems based on amplitude, frequency, or phase detectio...We propose and demonstrate free-space optical data links based on coaxial sidelobe-modified optical vortices（CSMOVs）. In contrast to the optical communication systems based on amplitude, frequency, or phase detection, the proposed scheme uses the radii ratio between the principle ring and the first sidelobe of the CSMOV.Therefore, the demand of stringent alignment and/or accurate phase matching is released. We design and optimize a composite computer-generated hologram to generate a CSMOV with four topological charges（TCs）.Extracted from the images captured by a CCD camera, the radii ratio between the principle ring and the first sidelobe of different TCs are consistent with the theoretical values.展开更多
文摘Solar energy is regarded as one of the most plentiful sources of renewable energy. An extraordinary light-harvesting property of a germanium periodic nanopyramid array is reported in this Letter. Both our theoretical and experimental results demonstrate that the nanopyramid array can achieve perfect broadband absorption from 500- to 800-nm wavelength. Especially in the visible regime, the experimentally measured absorption can even reach 100%. Further analyses reveal that the intrinsic antireflection effect and slow-light waveguide mode play an important role in the ultra-high absorption, which is helpful for the research and development of photovoltaic devices.
基金partially supported by the National Nature Science Foundation of China (Nos. 61138003, 61427819, and 61405121)the Natural Science Foundation of SZU (No. 201454)the startup funding of SZU (Nos. 000011, 000075)
文摘We propose and demonstrate free-space optical data links based on coaxial sidelobe-modified optical vortices（CSMOVs）. In contrast to the optical communication systems based on amplitude, frequency, or phase detection, the proposed scheme uses the radii ratio between the principle ring and the first sidelobe of the CSMOV.Therefore, the demand of stringent alignment and/or accurate phase matching is released. We design and optimize a composite computer-generated hologram to generate a CSMOV with four topological charges（TCs）.Extracted from the images captured by a CCD camera, the radii ratio between the principle ring and the first sidelobe of different TCs are consistent with the theoretical values.
