Symbol n
n is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
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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.
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Equation 8 · Scientific Methods
How Scientific Instruments and Metrology Actually Work
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text.
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.