Fig. 1. (a) Displacement vector diagram for intramolecular vibration at 9.72  cm−1 for cytochrome c, calculated using quasi-harmonic mode analysis. Transition dipole is indicated by the red arrow. (b) Calculated polarization dependent absorption from the intramolecular vibrations for cytochrome c.

Fig. 2. Top, schematic of MOSTS optics; yellow arrows show direction of incident THz polarization. Bottom, photos of the sample rotator.

Fig. 3. MOSTS signals for an isotropic silicon wafer and for an anisotropic sample, a polarizer. (a) MOSTS time domain signal. Inset shows a standard THz TDS transmission measurement for the silicon wafer to contrast with the zero MOSTS waveform because MOSTS only measures anisotropy in the sample. (b) MOSTS field amplitude showing the broadband anisotropy of the polarizer and, again, zero signal for the isotropic silicon.

Fig. 4. Absorption coefficient and refractive index measurements of c-face oxalic acid dihydrate single monoclinic crystals measured using THz TDS. Measurements shown are for the THz electric field parallel to the crystal’s a axis and parallel to the b axis.

Fig. 5. MOSTS modeling and measurements of a c-face oxalic acid dihydrate single crystal. (a) Calculated MOSTS waveform from parameters extracted from Fig. 4. (b) Measured MOSTS waveform. (c) Calculated MOSTS field amplitude spectrum. (d) Measured MOSTS field amplitude spectrum.

Fig. 6. Absorption coefficient and refractive index measurements of a-face sucrose single monoclinic crystal measured using THz TDS. Measurements shown are for the THz electric field parallel to the crystal’s c axis and parallel to the b axis.

Fig. 7. MOSTS modeling and measurements of an a-face sucrose single crystal. (a) Calculated MOSTS waveform from parameters extracted from Fig. 6. (b) Measured MOSTS waveform. (c) Calculated MOSTS field amplitude spectrum. (d) Measured MOSTS field amplitude spectrum.

Fig. 8. (a) Absorption coefficient and refractive index measurements of c-face sucrose single monoclinic crystal measured using THz TDS. Measurements shown are for the THz electric field parallel to the crystal’s a axis and parallel to the b axis. (b) MOSTS field amplitude.

Fig. 9. (a) THz TDS measurements of sucrose-polycarbonate model sample with THz polarization along the a axis of the sucrose (0°) and along the b axis (90°). (b) Difference in the absorption coefficient measured in (a) showing no obvious frequency dependent features. (c) MOSTS waveform of model sample and (d) field amplitude of MOSTS signal showing clear resonances at 1.55 and 2.05 THz as seen for the c-cut sucrose in Fig. 8(b).