Figure 5

a Goodness of fit χ² values, b microsphere apparent radii, c apparent refractive indexes and d mean TE-TM mode spacings obtained from the EMT fit on the WGM spectra of 50 fluorescent microspheres labeled on the x axis. The black dots are for a 3.3E–12 M (1.9E9 spores/ml) solution of B. globigii spores while the open squares are for the control sample in DI water. The gray line represents the threshold (3σ, 99.7% confidence interval) for biodetection occuring above the line in (a) and (c), but below it in (d)