Spatial resolution of fluorescent (FL) and SPR imaging using fluorescent point-source nanospheres. A) Transparent coverslip a 0.17 μm diameter particle fluorescing at 515 nm peak emitting wavelength in epi-fluorescent mode. Line scan plot next to image is used to determine full width half-maximum (FWHM) at 0.29 μm for a 1.65 NA objective. B) SPR image of nanoparticle at 620 nm shows a FWHM of 0.3 μm in the x-direction (red) and 0.6 μm in the y-direction using the 1.65 NA objective. The scale bar of 2 μm applies to A and B. Nanoparticle measurements made under water media, and fluorescence emission collected with 530 nm bandpass filter.