Photoluminescence excitation of lithium fluoride films by surface plasmon resonance in Kretschmann configuration

We report on excitation of the photoluminescence of lithium fluoride by means of the surface plasmon resonance of Al layer. Advantage of this method is high efficiency of the excitation, which is applicable to ultrathin films. P-polarized UV diode laser light is coupled to the surface plasmon resonance using a fused silica prism in Kretschmann configuration. The angular dependence of the reflected intensity is measured using a theta-2theta goniometer. The surface plasmon at resonance condition induces photoluminescence in the adjacent lithium fluoride layer. The fluoride layers were deposited on Al-coated fused silica substrates by electron beam evaporation. For the experiment, we prepared several samples with thickness ranging from 20 to 71 nm. We studied the effect of the luminescence enhancement by the surface plasmon resonance effect. Strong quenching effect was observed in the thinnest LiF layer. Influence of X-ray irradiation on the photoluminescence was studied.