I know that they are sharper than a normal weapon, but what is the most they can cut threw? Can they cut threw normal metals and glass?

They have a mono molecular edge.

So its down to atoms in width at its edge.

They can probably cut through metal easier than a standard weapon but really the cutting power is down to how much drag the blade has once the cut been made. A crude blade may have a mono edge but the non edge section of the blade is so rough that it catches and slow the blade down.

Thats the principle idea behind a samurai sword the high level of polish on the blade means its very very smooth and cuts cleaner meaning less drag and a deeper cut for the same effort.

How sharp? Very sharp.

You can actually acheive a 'mono' edge by knapping obsidan (a neolithic technology), but the edge is very fragile. A given objects ability to cut through something is not just about how sharp it is, but also how hard, a mono-molecular edged bar of soap will still obviously not cut through steel. However, a mono-edged pure carbon blade would slice through pretty much anything with ease, probably cut a person in half with the flick of a wrist. again though, the mono-edge would be difficult to keep even with very strong materials (carbon) and it would take speicalist equipment to keep the edge.

assuming a mono-blade is made of a suitably hard material, yes, there is no reason why it could not cut through glass or steel.