Why do microscopists use blue light rather than white light to see detail?

Answer 1

My guess is better optics. Different wavelengths of light travel with slightly different speeds in glass and refract at slightly different angles. Using one frequency of light would aovid 'fuzziness' caused by the varying refractions angles of a broad spectrum of light, i.e., white light.

Besides, it looks pretty.

Edit:

P, above, is right that blue light, which has a shorter wavelength than red light, will give you a higher resolution potential than red light. For that matter, purple will give you even better resolution, but the human eye does not see purple as well blue, so blue is the frequency of choice. But even red light will give you better resolution then white light.

Second Edit:

The word for what I was describing above is chromatic aberration. See http://en.wikipedia.org/wiki/Chromatic_aberration . Best way to avoid this is to have a very narrow frequency range.

I also learned something today. Some microscopes have apochromatic lens. See, e.g. http://en.wikipedia.org/wiki/Apochromat . This can lead to inserting a set of special seven lens. See, e.g., http://micro.magnet.fsu.edu/primer/anatomy/aberrations.html .With this combination, you are suppose to reduce the chromatic aberration by an order of magnitude.

I was unable to find out if the diffraction error caused by white light is less than the chromatic aberration error (refraction errors) caused by white light.

Answer 2

blue has a shorter wavelength, so you can resolve smaller 'things', but you can still see it with your eye. (blue about 400nm, red about 700nm, it's quite a difference)

beyond that there's electron microscopes with tiny wavelengths so you can resolve teeny things and stuff! but you wont see anything with your eye

+++++
actually, no. red is bad for resolving. at least white would give you a small amount of the power of blue, just because of the blue in it.

look at the wavelength dependance of the resolution

http://en.wikipedia.org/wiki/Diffraction-limited
http://en.wikipedia.org/wiki/Resolving_power
right at the bottom. (lower R is better)

Answer 3

It's much PRETTIER!

(Actually P is right)