Spectral characterization of materials using terahertz time domain spectroscopy (THz-TDS)

[摘要] ENGLISH ABSTRACT: Terahertz (THz) radiation is often used in many promising applications such as informationand communication technology and airport security. Optimized and adapted terahertz fieldshold huge promise for leading this technology further. This study is focused on terahertz timedomain spectroscopy (THz-TDS). In THz-TDS the electric field is measured, therefore bothamplitude and phase information of the THz pulse can be obtained. We used the pump-probetechnique in order to measure a THz pulse from the photoconductive antenna. A pulsed fiberlaser with FWHM of ' 100 fs was used for this. The frequency spectrum of the measured THzpulse was obtained via a fast Fourier transform. We studied the principles of the THz pulsegeneration as well as detection, with a photoconductive antenna as emitter and detector. In thisstudy terahertz spectroscopy has been used to investigate the refractive index and absorptioncoefficient of different types of materials in the terahertz region. The last part of this study dealswith a simple process for material parameter extraction of a polymer sample using commercialsoftware called Teramat1.0. It uses the sample thickness, the reference THz pulse and thetransmitted THz pulse to retrieve the complex refractive index of the sample.

[发布机构] Stellenbosch University