Electromagnetic energy concentrator with frequency shift - uses dopant that responds to electromagnetic excitation by emitting light at different frequency

摘要

The concentrator has a transparent matrix (4) with a coating over parts of the matrix. The coating has a high reflectivity at one wavelength and a high transmissivity at another wavelength. The transparent zone has optically active dopants absorbing energy at one wavelength and transmitting it at another wavelength. The excitation wavelength is in the transmission band for the reflective coating, and the emission wavelength is in the reflective band for the coating. The concentrator thus acts as an 'electromagnetic diode', showing different behaviour dependent on the direction of arrival of the electromagnetic signal. ADVANTAGE - Improved detection of illumination by laser to warn military target that it has been scanned, or can be used to improve efficiency of photovoltaic cells.