Temperature Measurement Using Light Beam Diffraction
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18
This article relates generally to temperature measurement and more particularly to such measurement by sensing the amount of change in the refractive index of a gas enveloping a hot body. Measurement of the temperature is accomplished by immersing a hot body of unknown temperature in an inert atmosphere of a noble gas. The hot body establishes a temperature profile and produces a corresponding change in the refractive index of the gas. A laser beam directed through the gas adjacent to the hot body is deflected from a normal impingement point by the refraction. The amount of deflection can be measured, and the temperature determined by comparing the resulting deflection with known, calibrated deflections versus temperature. This technique enables high spatial resolution and, thus, sensitive temperature measurement.