Photothermal deflection spectroscopy
From Wikipedia, the free encyclopedia
 |
It has been suggested that this article or section be merged with Photothermal spectroscopy. (Discuss) |
 |
This article is orphaned as few or no other articles link to it. Please help introduce links in articles on related topics. (August 2007) |
Photothermal Deflection Spectroscopy is a kind of spectroscopy that measures the change in refractive index due to laser heating of a surface. It works via the mirage effect where a refractive index gradient exists adjacent to the substrate's surface. The test laser beam is diffracted or bent in a manner proportional to the temperature of the surface. From this the ratio of absorption over scattering can be determined.
It is of particular value in situations where "pass through" or transmission spectroscopy can't be used.
Typically the surface is heated using a pulsed light source. A lock-in amplifier is then used to measure deflections found at this frequency.
