Transmission, reflection and absorption of light incident on metallic hole arrays

In case of metallic hole arrays we need to establish how structures transmit, reflect and absorb light. We fabricated hole arrays using a focused ion beam etching system (FBI DB235). The period of the array was 430±5 nm, the hole diameter 250±5 nm and the thickness of the silver 180±5 nm. We made arrays with relatively large dimensions, 1 mm² so as to make the measurement of the reflectivity possible with existing facilities. We next performed optical measurements to find the transmittance and the reflectivity as a function of incident angle and incident frequency. In this way we are able to build up a map of the dispersion of the surface plasmon (SP) modes associated with the enhanced transmission.