Patent ID: 7876423
Filing Date: 2011-01-25
Classification: G01B,G01J,G01N

Abstract:
1. A process for measuring the velocity of terahertz electromagnetic radiation in a material sample without prior knowledge of the thickness of said sample, said terahertz electromagnetic radiation produced by a source, namely, a transceiver, spaced apart from said sample under test and propagated at the speed of light, c, in a medium located between said source, namely, said transceiver, and said sample, said sample residing on a substrate, comprising the steps of: emitting terahertz electromagnetic radiation from said source; measuring the travel time of said terahertz electromagnetic radiation to and from said substrate without said sample present, t″; placing said sample on said substrate; measuring the travel time of said terahertz electromagnetic radiation to and from said substrate with the sample present, t′; subtracting t″ from t′ to determine the transmission time difference with said sample present and without said sample present, Δt; measuring the travel time of said terahertz electromagnetic radiation to and from said sample, 2t determining the time difference between t′ and the 2t dividing Δt by 2τ and determining the quotient; subtracting said quotient from 1 to obtain a factor; and multiplying said factor by, c, to determine the velocity of said terahertz electromagnetic radiation in said sample.