On-chip time domain terahertz spectrometer with rapid sample exchange

Free-space time domain THz spectroscopy is a powerful technique that struggles to measure samples physically smaller than the diffraction limit (~0.3 mm), such as van der Waals materials and heterostructures. We present an on-chip, time-domain THz spectrometer based on photoconductive Auston switches. Our spectrometer features an interchangeable sample architecture with a usable bandwidth of 100 GHz to 800 GHz. We qualify our spectrometer using the superconducting transition in 6-um wide superconducting NbN films, ~40 times smaller than the wavelength at 800 GHz.