Patent ID: 7352449

Claim:
A method for detecting materials, comprising the steps of: applying tera-hertz waves of a plurality of different frequencies around a boundary between a light wave frequency and a radio wave frequency to a predetermined position of an inspecting object by using a tera-hertz wave applying means; and detecting the presence or absence of a detecting material by determining whether or not an output wave includes a detecting spectrum of the detecting material, wherein the output wave is the tera-hertz wave that has been applied to the inspecting object, wherein the tera-hertz wave applying means includes white light applying means for applying white light of a plurality of different frequencies to the inspecting object, and wherein a spectrum obtaining means for performing Fourier transformation on the output wave to obtain a spectrum formed by the respective different frequencies is used to receive the output wave and to determine whether or not the output wave includes the detecting spectrum of the detecting material.