# Extinction/Absorption/Transmission spectra

1. Oct 19, 2009

### krindik

Hi,
This must be a text book question but I couldn't find exact definitions(quantitative) of these measurements
Extinction spectra:
Absorption spectra:
Transmission spectra:

eg.
Lets say electric field spectrum of some location/surface is calculated by illuminating a source with and without the presence of an object.
With the presence of the object = $E_{transmitted}(\omega)$
Without the presence of the object = $E_{incident}(\omega)$
Absorption spectra = $$\frac{E_{incident}(\omega) - E_{transmitted}(\omega)}{E_{incident}(\omega)}$$
Should it be $E$ or $E^2$ (energy) ?

Can somebody point me to a book/ web resource or the answers to these definitions?

2. Oct 19, 2009

### Andy Resnick

Usually the absorption, reflection, and transmission spectra are given in terms of the absorbed, reflected, or transmitted *energy* (intensity) sisnce that is what is measured. Also, the spectra are (usually) obtained by normalizing to the incident energy, to remove dependence on the source illumination.

3. Oct 19, 2009

### krindik

Could you give the exact definitions? Or any book?