microscope

[gusl]

Single molecule, one million times smaller than a grain of sand, pictured for first time

Is the world's finest microscope based on touch, rather than optics? It's interesting that what you see is forces, rather than the "surface" of the molecule. I put "surface" in quotes because bonds are just forces... What's the smallest thing that has been seen with optical equipment?

Comments

[bluebear2.livejournal.com]

I always figured they would be round.

[gustavolacerda.livejournal.com]

who is they?

[wjl.livejournal.com]

presumably the molecules?

[bhudson.livejournal.com]

Is the world's finest microscope based on touch, rather than optics?

Yes.

[gustavolacerda.livejournal.com]

is there a fundamental limit here?

I suspect that atoms and molecules don't reflect light the same way as macroscopic objects do.

[bhudson.livejournal.com]

For starters, there's the nyquist limit: you can only see features twice as large as your wavelength (unless you have some prior knowledge). As the optical wavelength shrinks, energy rises, until you get to where just by looking you're dissociating the molecule.

To say anything more would require me to actually know something, which I don't.

[gustavolacerda.livejournal.com]

I didn't know that the Nyquist limit applied to spatial signals (i.e. vision), though I understand why you get Moiré patterns.

<< (unless you have some prior knowledge) >>
heh, Bayesians claim a free lunch!


<< until you get to where just by looking you're dissociating the molecule. >>
Presumably, force-based microscopy will also have a limit like this, in which touch screws up the thing you're observing... and this might be our last limit, putting a bound on fundamental knowability.

[bluebear2.livejournal.com]

Didn't some wise old Chinese guy hundreds of years ago say that the observer alway affects the observed?

[afanesvoltaje.livejournal.com]

awesome!

[easwaran.livejournal.com]

I didn't think this was anything new - Matt's always using an AFM to look at nanocrystals that he grows on things. I think some of the pictures he showed me even had atomic level resolution like this. I suppose they're always of larger crystalline semiconductors though rather than individual organic molecules.

He tells me that the new molecular foundry (where he does some of his work) at Lawrence Berkeley Lab was actually designed to be shaped like an AFM cantilever. I don't actually know what either the building or the microscope look like though, so I can't say how close the resemblance is.

Although I think he does use electron microscopes more often (I think he mentions both scanning and tunneling, or at least I hear the acronyms "SEM" and "TEM" from him a lot) - which of course are more sensitive than optical microscopes (because electrons have smaller wavelengths).

[kartiksg.livejournal.com]

On that scale... think for a minute... what is "touch"?

Yay E&M at work