THz Mach-Zehnder Spectrometer

Polarization RotatorCharacterization of semi-transparent materials requires a THz Mach-Zehnder inferometer (shown below), since no etalon fringes can be observed in the transmission spectra of such materials. The Mach-Zehnder setup enables measurements of a phase shift induced by the sample as a function of frequency. Combining this data with transmission spectrum, real and imaginary parts of the dielectric constant can be calculated.

Highly absorptive materials can only be characterized in a reflection geometry, illustrated below.