Is it possible to construct a mirror such that it only reflects certain wavelengths of visible light while allowing other wavelengths of visible light to pass through? I was reading about microwave ovens and how the doors are designed to block microwaves from exiting the oven and was wondering if the same principle can be applied to visible light.
Thanks!
You could look at Optical coatings and dichroic filters.
Optical coatings are many thin layers of material of two of more different refractive indices, about one light wavelength in thickness. They structure of the coating can be designed for high reflectivity at some wavelengths and low reflectivity at others, but the switch-over cannot be too abrupt. They are very expensive to make.
Microwave oven doors work on a different principle. The holes are about 1mm diameter. Visible light passes through easily because the wavelength is very much smaller (about 0.5 microns = 0.00005cm) whereas for microwaves the wavelength is very much bigger than the holes (about 12cm). As far as the microwaves are concerned, the grille is not much different from a mirror. See How does the grid on the microwave oven window prevent microwave radiation from coming out?.
If the same principle were used for visible light, it would be difficult to get a relatively "sharp" cut-off between 2 wavelengths. But it could be done, using nano-structured materials. Fine-structuring could produce exotic optical properties. See also meta-materials.
There are mirrors which reflect only particular color wavelengths and not the others. There are mirror which can reflect particular symmetry and not the other. By using proper coating and proper atomic symmetry elements we can develop different kinds of mirrors. In Kurukshetra, India In science panaroma, both these kinds of mirrors are available, Where people look at the alphabets of different colors and there are only few colors which gets reflections others dont. There is this mirror which can reflect bisymmetric alphabets like T or I but not G or K etc.
