Supplementary Figure 2: SLAP Excitation Efficiency.
a) Excitation efficiency (the number of fluorescence photons collected as a function of average excitation power) for SLAP and raster scanning, measured for fields of view with different degrees of sparsity. Recordings were performed in a fluorescent plastic block (Chroma Technologies), with sparsity artificially imposed using the SLM. Photon rates were measured by summing photodetector current and dividing by the known mean current for a single photon. Lines are quadratic fits (forced 0-intercept) to the measured points. b) Power required to achieve a brightness of 10,000 photons per second per square micron, for SLAP and raster scanning, computed from quadratic fits in (a). The power required by conventional raster scanning is independent of the sample. The power required by SLAP is linear in the SLM open area, with non-zero intercept due to the imperfect extinction of excitation light by ‘OFF’ pixels of the SLM. SLAP and raster scanning have equal efficiencies for fields of view with approximately 2% of pixels labelled. SLAP efficiency could be further improved by increasing the extinction of the SLM. Experiment was performed once.
