Ocean Optics Overture - Manual (Page 9)

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Chapter 1
Introduction to Spectroscopy
Spectroscopy in a nutshell
A spectrometer is a device that breaks up light into different colors by spreading out, or dispersing
different wavelengths. Rain does this by
refraction of light, creating a rainbow that goes from violet
through yellow and then red.
This spread of colors is called the visible spectrum. Humans can see light between 380nm (violet) and
780nm (deep red). Other creatures can see different ranges.
You can get the same effect by reflecting light with a CD. The very fine markings on a CD are so small
that they are getting close to the wavelength of light and cause the diffraction of light into a spectrum. The
CD surface is acting as a
diffraction grating . In fact it is a reflecting diffraction grating .