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New Electron Microscope Shows Atoms in Color
Cornell's Duffield Hall has acquired a new electron microscope that is enabling scientists to see individual atoms in color for the very first time. While old electron microscopes can be compared to black and white cameras, this new scanning transmission electron microscope uses a new aberration-correction technology that is both more intense and allows for faster imaging speed. "The method also can show how atoms are bonded to one another in a crystal, because the bonding creates small shifts in the energy signatures. In earlier STEMs, many electrons from the beam, including those with changed energies, were scattered at wide angles by simple collisions with atoms. The new STEM includes magnetic lenses that collect emerging electrons over a wider angle. Previously, Silcox said, about 8 percent of the emerging electrons were collected, but the new detector collects about 80 percent, allowing more accurate readings of the small changes in energy levels that reveal bonding between atoms."
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
It isn't so much a question of reflection, but more of capturing the excitation of electrons in the atoms that make up the sample by absorbing the irradiated energy. The electrons are excited into higher orbits, which gives off light that the "camera" on this microscope captures and resolves into a cleaner image. That is why organic samples are pretty much goners in EMs. They can't survive that much radiation.
Absolute power corrupts absolutely. indymedia
I'd like to see these atoms rendered in necessarily false color (they're smaller than visible light wavelengths) that is at least the color corresponding to their size. They're smaller than visible wavelengths, but their actual size is a specific fraction of a visible wavelength. Let's see the atoms colored with the color that's a harmonic multiple.
Or maybe the color should be derived from the "texture" of the atom, just like the actual color of macroscopic materials. If a carbon atom has 12 electrons evenly distributed around a sphere in shells (2, 8 and another 2 in valence), let's see it get colored accordingly. Maybe the inner shell's diameter harmonic color in the visible range, divided by 2 and scaled back into the visible, overlapped with the same algorithm for the outer 8 in the second shell, then again for the 2 in the outermost shell.
The point is that these colors can mean something. And since the number and combination of electrons is so important to the characteristics of the electron, as well as offering the femtoscopic equivalent to macroscopic colored surfaces, I'd like to finally see what I've been imagining since high school chemistry class.
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The color is based on the energy of the electrons, just like photon "color" is based on the energy of individual photons. The microscope is "color" because it can record the energy of the electrons as well as their density. Thus it is "color" just as much as your eyes - which measure photon energy (cone cells of 2 to 3 or in some cases 4 types) as well as photon density (rod cells). Note that your cone cells require more light to get a color signal. In dim light, you see black and white via your rod cells only - the situation with earlier electron microscopes. By increasing the electron capture 10 fold, true electron color vision is enabled.
The scientists quoted are top notch. I used to work with David Muller, and you can trust this to be both scientifically sound and bleeding-edge technically.
I was *almost* doing this in the 1990s. I could have showed you a coloured image at atomic resolution with colours based on EELS spectra, but IIRC the contrast was mainly from electron-channeling and therefore bullshit. I'm confident that these guys have eliminated such effects.
The uses of this technology in materials science will be enormous.
In theory, there's no difference between theory and practice; in practice there is.