Distance measurement

sid_galt

How are distances on the order of microns or nanometers measured for objects like say a bacteria or a very small component of a device where distance measurement through interference of light isn't very feasible?

willib

relative distance or exact distance..?
it is a lot easier to get relative distance than exact..

sid_galt

Well, exact distance.
Can't you get that by doing a series of relative measurements?

And anyhow, how do we measure relative distances?

morry

Can electron microscopes help here? I know they can see stuff smaller than the wavelength of light.

sid_galt

They are very expensive even if you try and make one yourself. I am sure there are other more cost effective methods.

As for wavelength of light, that depends on what wavelength you are referring too.

Q_Goest

Sid, not too sure what you want to measure, but mechanical parts are often measured using something called an optical comparator. Most precision machine shops have these things, and I'm sure if its use were applicable you could use one without having to pay for its use. It only takes a few seconds to measure something with it, and you don't need any experience or special knowledge to run one. They can measure lengths down to about 0.0001" or less. Here's a link to a description: Comparator