PLOTS Spectral Workbench: index

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What is spectrometry?

Spectrometry can reveal the composition of unknown materials -- either from samples you take from a site, or (with more difficulty) from a distance. It is used by NASA to identify substances on other planets. Typically, full-spectrum light (such as the sun) shines through a thin slice of the sample, which filters (absorbs) certain colors and allows others to pass through. This light can be split up by color using a prism, and the missing (absorbed) colors can be identified. Finally, the brightness of all the colors is compared to a database of known samples to find a match.

Things can get more complicated, as when there are multiple substances in a sample, or when a substance is dissolved in water. Spectrometry is a broad and complex field, but some simple techniques have been successfully used in the field -- such as identifying Poly-Aromatic Hydrocarbons (PAHs, a common contaminant from oil) by shining strong UV light through a sample, and measuring what colors it fluoresces. You can read more about the kinds of spectrometry we're attempting on the PLOTS website.

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Compare Warm, Neutral, and ...

JoshMc | 3 spectra

Cree XM-L LED's in SWM V1xR.

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393nm UV Tests

JoshMc | 8 spectra

393nm UV shown through various materials. The samples were placed in a clean baby food jar between the light source and the spectrometer. The baby food jar itself was tested empty and made no mea...

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