Optical dew sensor using surface plasmon resonance of periodic Ag nanostructure

The sensitivity of an optical dew sensor is enhanced by the use of the surface plasmon resonance (SPR) of a periodic Ag nanostructure. As the temperature of an SPR-excited Ag nanostructure decreases, vaporous water molecules. condense and adsorb onto hydroxyl groups formed on the Ag surface. A redshift of 40 nm in absorption peak wavelength, was observed owing to the amount of adsorbed water molecules due to the temperature. An SPR signal occurs at temperatures higher than the theoretical dew point and shows the sensitivity improvement of the optical dew sensor by the proposed SPR technique.