What does negative contrast look like?

[DemoniWaari]

I was trying to determine the best oxide thickness and material for maximising the contrast of one atom thick material layer on top of silicon chip. Using Fresnel equations I was able to do plot the contrast with respect to oxide thickness and wavelength, but alas, contrast seems to be sometimes negative.

So first I thought that there is something wrong with my code, but it works perfectly for graphene so that does not seem to be the case. I also checked that you can get negative contrast for graphene when there are enough layers, so maybe my result isn't completely wrong.

Thus what does this negative contrast look like? I want to know how easily one can see this one atom thick layer with a microscope, so I need some information on how I can interpret this result.

So, any help?

 

[Greg Bernhardt]

Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?

 

[bland]

I'm not going to pretend to understand the question fully, but nevertheless because negative contrast doesn't seem to make sense to me I was wondering if, like negative probabilities, it needs to be squared to get a positive value, or if indeed a negative value is the same as a positive value in this case... I'll get my coat...