The Optics of Polarization Sensitivity

No doubt it is foolish to assume without proof that organisms have solved a particular sensing problem in the same way that physicists and engineers have. The animal’s sensory requirements and biophysical repertoire may in fact be quite different from the corresponding human conceptual and instrumental systems. Thus visual polarizers in animals unlike instrumental polarizers which may be extremely specialized in their application, are part of quite general photoreceptor systems which ordinarily have also to discriminate intensity, wavelength, movement, images and so on. Consequently their functional design must involve appropriate compromises to maintain optimal sensing of all significant light parameters. Hence the sharing of input channels and the mechanisms of discrimination are of particular importance. Yet the signal parameters and potential optical means of estimating them are undoubtedly the same as for a manmade polarimeter.