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. 2006 Mar 24;90(12):4662–4671. doi: 10.1529/biophysj.105.079442

FIGURE 5.

FIGURE 5

The IPSF z-dimension profile for a unit magnitude dipole emitter perpendicular to the interface (μ⊥) under TIRM with and without a 30-nm-thick aluminum film. Excitation light incidence angle was chosen to produce evanescent field depths of ∼70 and 100 nm. Emission is collected from the glass medium over a surface area that covers the solid cone of fluorescence emitted from the dipole and transmitting the interface with polar angle 105° ≤ θem ≤ 180° measured from the z axis in Fig. 2 and appropriate for an NA 1.45 microscope objective. Collected fluorescence includes both SAF and subcritical angle fluorescence (Fig. 2). For the metal film, essentially all emission is SAF so the summation over subcritical angle fluorescence contributes negligibly to the IPSF z-profile. For the bare interface, subcritical angle fluorescence makes a substantial contribution to the IPSF z-profile.