spectral imaging, we first briefly discuss the two elements of the imaging process:
spectroscopy and imaging.
13.2.1 Spectroscopy
Spectroscopy is a broad and well-established science that has been used extensively
to explain the spectral characteristics of matter. The first use of spectroscopy dates
back to 1666, when Newton described the dispersion of white light into its constitu-
ent colors. Later, the same capability provided the spectrum of hydrogen, which was
explained by Balmer in 1885, eventually leading to the Bo
¨
hr model of the atom in
1913. The measured spectrum is related directly to the structure of the atoms and
molecules under examination and is a measure of their energy levels. Energy, which
is provided in microscopy applications by the ...