Recent work has shown that the layered antiferromagnetic metal Fe1/3NbS2 can be electrically switched using remarkably low current densities (on the order of 104 A/cm2). Electric and magnetic measurements of this material suggest threefold symmetry breaking in the ground state, indicating the presence of an unusual type of nematicity. In this talk, I will introduce the basics of the THz spectroscopy and describe how we used the THz-induced electro-optic effect to probe the Potts nematic ordering in Fe1/3NbS2. We observed a THz-induced ellipticity that persists at temperatures three times higher than the Néel temperature (50 K). Surprisingly, the predicted point group symmetry for this material forbids measurement of an electro-optic effect in our experimental geometry. I will also talk about the necessary conditions under which the Pockels effect could be observed in Fe1/3NbS2.