Energy up conversion caused by metallic photonic boxes

A photonic box structure is discovered to have the characteristic of transferring part of the input pumping 532nm laser energy to wavelength 300nm. The spectral width is narrower and the intensity is linearly increased as the intensity of the input laser increases. The spectral width shows an abrupt change when input laser power exceeds 30mW. The mechanism of this phenomenon is considered to be related to surface plasmon resonance, however, complete explanation cannot be obtained through known physics. This new energy transfer phenomenon gives us a new direction toward using the photonic box structure.