Fig 4. Transmission from back-illuminated guides.

Slide back-illuminated with 700 nm light (a) and 500 nm light (b). Intensity data was collected from sets of 2x2 pixel areas centered on the guides (red boxes). The background level was collected from a box centered in the dark region between guides (green box). Unattenuated light intensity was collected from the closest large defect (yellow box). (c) Transmission data vs. Wavelength; error bars are s.d. from measurements of multiple wells (N = 18). The model function was fit to the data as described in Methods. The grey ribbon corresponds to the uncertainty in the metal thickness z.