The discussion below refers to the following foto:
Wing of parasitoid wasp
Portrait of this wasp is shown here
Upper figure: 3 examples of reflection spectra.
White: The thickest part of the wing (gray) shows so many wiggles in the spectrum, that it appeares neutral grey for the eye (center part of the wing). Thickness (almost) 1.5 Microns
Green: somewhere in between, thickness 631 nm (which corresponds to one wavelength of visible (green) light. Note that there are several green regions, cf. discussion below.
Blue: Light blue at the very bottom of the smaller wing. This is the thinnest region, with only 260nm thickness.
Lower figure: From this (simulated) "wing" you can see, that the mapping color->thickness is not unique. Especially with growing thickness, green and magenta regions appeare periodically (albeit with vanishing saturation, as thickness increases). This effect can be seen nicely in the real wing (upper wing, start from right to left)
The analysis was made with the following optics:
Mitutoyo M Plan Apo 100x NA 0.70 tube lens: Thorlabs 165mm
Illumination: white coaxial lightning
