Incident light polarization dependence of terahertz emission spectrum of crystalline 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate

In this work we have measured the dependence of terahertz emission via optical rectification from the 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate crystal as a function of incident light polarization. Many structures, which varied depending on the polarization of the incident pulse, were observed in the frequency spectra. The observed structures can be explained by incorporating the refractive index dispersion, the response function, and the birefringence properties of the crystal into the mathematical model used to reconstruct the experimental data. Our results show that careful attention must be paid to these three properties when enhancing nonlinear susceptibility during the fabrication of efficient terahertz emitters.