Attempts were made to construct a plasmonic trap for cold atoms using a prism fabricated with a layer of gold film. We tried to detect the plasmonic evanescent field through two different methods: (i) optical fibre, and (ii) atomic force microscope (AFM) tip. We showed that the former method is inferior to the latter. Detection of the plasmonic evanescent fields were performed by modulating the incident beam and observing the corresponding modulation on the height of the AFM tip. This is then followed by the investigation of the dependence of the evanescent field strength on the polarization and the incident angle of the incoming beam. We showed that unwanted contribution due to scattering from the surface of a dirty prism is significant enough to drown signals from the plasmonic evanescent fields by comparing results from dirty and clean prisms. The stage has been set for the characterization of the plasmonic evanescent fields for prisms with various gold film grating configurations.