Sample Thickness Measurements Using Phase-Sensitive Terahertz Upconversion Detection

We demonstrate our work on phase-sensitive nonlinear upconversion detection of terahertz radiation, using an off-the-shelf sCMOS sensor. The terahertz radiation is upconverted to infrared light using a nonlinear medium and interferes with a second source of coherent light, which yields the phase relation between both sources. Using this approach, six individual single-layer samples were measured in transmission and compared to terahertz time-domain spectroscopy (TDS) measurement results.