Birefringence measurement in the THz range based on double Fourier analysis

A method for obtaining the average refractive indexes of a birefringent material in the terahertz region in a single measurement with a standard terahertz time-domain spectrometer is presented. The method is based on processing the frequency-domain interference between terahertz pulses and echoes through the Fourier transform of the terahertz spectrum. The technique also allows the determination of the optical axis orientation of the material by making two measurements with different angles of the sample optical axis. (C) 2014 Optical Society of America
The authors thank the Erasmus Mundus scholarship and the Consejo Nacional de Investigaciones Cientificas y Tecnicas (Conicet) that support the work of Federico Sanjuan at Universitat Politecnica de Valencia and the Spanish Ministerio de Economia y Competitividad for partially supporting this work through project TEC2012-35797. Federico Sanjuan also thanks Dr. Jorge Tocho for his encouragement and support.