OU NanoLab/NSF NUE/Bumm & Johnson
Extension
to Scattering and Extinction
•Attenuation of light by absorption and scattering both
obey Lambert’s Law. Thus we can extend our treatment of
absorption to scattering and extinction. (Recall that extinction is the effect of
absorption + scattering.)
•The scattering efficiency can be
much larger than unity.
•Extinction paradox: Qext = 2 (Qabs = 1; Qsca = 1)
for an perfectly
absorbing particle very large compared to the wavelength of light.
•Note:
•All of these quantities are in general wavelength
dependent.
•Our discussion has not included the mechanism (cause) of
absorption and scattering.
•There are many different mechanisms that cause of absorption and
scattering.