Simultaneous Measurement of Orthogonal Terahertz Fields Enabled Via a THz MODEM (modulator/demodulator) Scheme

A scheme is proposed and demonstrated that realizes the rapid simultaneous measurement of orthogonal terahertz fields. A fibre-coupled multi-pixel THz emitter on InGaAs generated orthogonal polarization states, with a dynamic range and bandwidth comparable to a commercial antenna. We developed a dual-frequency modulation/demodulation scheme that used a conventional photoconductive detector to record the orthogonal polarization states. This work has significant potential to improve the speed of polarization-resolved THz spectroscopy and imaging. We demonstrate its efficiency by characterizing birefringent crystalline materials and anisotropic metamaterial.