In the Fourier transform measurement method, many different wavelengths of light are received by a single detector, which measures the intensity of each wavelength over time and then determines changes in intensity for each frequency, or wavelength.

<Infrared Rays>
This FT-IR operates on exactly the same principles as a microwave oven, which works by radiating a material with electromagnetic waves, a process that accelerates the activity of water molecules, causing them to produce energy in the form of heat. This heat energy raises the temperature in the radiated object. Infrared rays have a shorter wavelength than the electromagnetic waves generated by microwave ovens. Infrared rays are absorbed into some objects, depending on the structure of the molecules that compose it. Our body also absorbs infrared rays. The wavelength of infrared rays and the strength of their absorption vary depending on the material. Therefore, when we expose a material to infrared rays at different wavelengths, we can differentiate the wavelengths of those infrared rays that have been absorbed into the material from those that were not. Everything has a unique reaction to exposure to infrared radiation, and this mechanism can be used to identify the composition of samples, much like identifying a person by their fingerprints. Databases containing such reference signal patterns are available on the commercial market. By using HORIBA's FT-IR, you can match a material's signal pattern to the appropriate reference signal pattern to easily identify what the material is. For example, our FT-IR was used help resolve a recent health scare by determining the composition of an unknown powder that was contaminating a soft drink. The quality control section of some department stores also uses an FT-IR to assure that the ingredients of products contain the standard quantity of ingredients as stipulated in the specifications. Our FT-IR is also used for criminal investigations by police throughout Japan. Furthermore, in archeology, the threads of burial shrouds can be studied with our FT-IR, which can determine whether the material's threads are made of cotton, or silk, or animal hair. As the possibility of mounting an FT-IR in ADEOS (a Japanese satellite) was once discussed by the Ministry of International Trade and Industry of Japan, someday our FT-IR may travel into space.

The mechanism of the FT-IR has been applied to some of HORIBA's exhaust gas analyzers for automobiles, which can simultaneously analyze the different ingredients of automobile exhaust gases.