Equation 7 · How Scientific Instruments and Metrology Actually Work
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the wavelength of the illuminating radiation, and n is the numerical aperture of the imaging system. Read the equation part by part below; each part has a contextual explanation and a link to its mathematical background.
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Symbol λ
the wavelength of the illuminating radiation, and n is the numerical aperture of the imaging system.
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where is the wavelength of the illuminating radiation, and n is the numerical aperture of the imaging system. For visible light this caps optical microscopy at roughly 200 nanometres — far too coarse to resolve individual atoms, whose spacing in a solid is typically a few tenths of a nanometre. Electron microscopy exploits the far shorter de Broglie wavelength of accelerated electrons — picometre scale at typical accelerating voltages — to push the diffraction limit itself down by more than three orders of magnitude.
Sources cited in the article section
- [8] Imaging single atoms using secondary electrons with an aberration-corrected electron microscope ↗
- [7] Electron ptychography of 2D materials to deep sub-ångström resolution ↗
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