Medición de materiales con radiación Terahertz.

Terahertz (THz) radiation or T-Ray defines electromagnetic waves with a frequency range between 0.1 THz and 10 THz. It is possible to categorize radiation detection techniques in the THz band in coherent and incoherent techniques. The main difference between them is that in the coherent technique, both the amplitude and the phase of the received signal are determined; but, in the incoherent technique, only the intensity of the signal is measured. THz spectroscopy in the time domain is generally a coherent method. Direct detectors such as pyroelectrics are mainly incoherent detectors. This article presents the experimental measurement of different materials when irradiated with terahertz radiation, applying THz spectroscopy techniques in the time domain. The radiation is emitted by a photoconductive antenna, excited by a femtosecond laser. The results are obtained by measuring the THz pulse transmitted through the materials by implementing coherent and incoherent detection systems, analyzing the data obtained, it was possible to obtain the refractive index and absorption coefficient, in case of the coherent technique, and the absorption coefficient in the incoherent technique, for the different materials studied in this work. With these results, it is concluded that it is possible to perform a characterization of different types of materials when irradiated with THz radiation, which leads to various applications from safety to quality control. [ABSTRACT FROM AUTHOR]