Fig. 5.

A 12-μm section of murine ear stained with anti-EGFR-${\mathrm{NaYF}}_4:{\mathrm{Yb}}^{3+}$, ${\mathrm{Er}}^{3+}$ nanoparticles, false colored green here. The grayscale images shown are tissue autofluorescence at 460 nm following 780 nm excitation. UNP emission was collected at 665 nm following 980 nm excitation. Images were 510 by 510 pixels and represent a 400 μm field of view. Dwell time was 9.2 μs per pixel. The excitation power density was $21\mathrm{kW}/{\mathrm{cm}}^2$ for the upconversion luminescence image and $\sim 10\mathrm{MW}/{\mathrm{cm}}^2$ for the autofluorescence image. (a) Full image before deconvolution. The arrows at top and bottom represent the location of the profile shown in (b). (b) Profile taken along a single scan line of an image of upconverting nanoparticles bound to tissue. The dashed line is equivalent to the PSF used for deconvolution, shifted and scaled to overlap with the rise and decay of a single particle. PSF amplitudes were set equal for simplicity. (c) The same profile following deconvolution with the PSF shown in the left image. This profile is the result obtained following 60 iterations of R-L deconvolution. (d) Full image after deconvolution of each line along the fast-scan axis.