The spiral plasmonic lens is capable of focusing the left-hand and right-hand circular polarizations into spatially separated plasmonic fields caused by the geometric phase effect. Its function as a circular polarization analyzer has been studied analytically and numerically in a previous Letter [ Opt. Lett. 34, 3047 (2009)]. Single Archimedes’ spiral grooves with lateral sizes of approximately $4{\lambda }_{\mathrm{spp}}$ (~2.8 μm) were milled into a gold thin film by using a focused ion beam. The function of such a simple spiral plasmonic lens serving as a circular polarization analyzer was experimentally characterized with two-photon fluorescence microscopy. The circular polarization extinction ratio of the two-photon fluorescent signal is estimated to be larger than 200 for a detector diameter up to $0.3{\lambda }_{\mathrm{spp}}$