Low-noise terahertz material parameter extraction using a spinning wheel

We demonstrate measurement of material optical parameters, in the THz regime, by mounting the sample under test on a spinning wheel. The proposed measurement technique is implemented using double-modulated terahertz differential timedomain spectroscopy (double-modulated THz-DTDS). Spinning sample addresses fundamental limitations imposed by linear sample dithering. The concept of spinning the sample allows rapid switching between the reference and sample signals with a single mechanical delay scan. We validate this technique by measuring the dielectric properties of thick polymer material.