Laser-induced fluorescence within subwavelength metallic arrays of nanoholes indicating minimal dependence on hole periodicity

Fluorescence measurements are obtained in transmission from a thin film of rhodamine 6G molecules immersed into a 40 nm thick polymethylmethacrylate film, which has been spin coated onto an array of nanoholes in a thin gold film. The fluorescence is shown to be minimally correlated to the white light spectra of the same films and not highly dependent upon film periodicity, but rather highly dependent upon hole size and shape. The authors suggest that the spectroscopic signature originates from a determination of the allowed modes inside of the hole, which are recognized by the excited state molecular fluorophore before the radiative field is generated. (c) 2007 American Institute of Physics.