| Autor: |
Potts AM; Department of Physics, University of California at Santa Barbara, Santa Barbara California 93106, United States., Nayak AK; Department of Physics, University of California at Santa Barbara, Santa Barbara California 93106, United States., Nagel M; Protemics GmbH, 52074 Aachen, Germany., Kaj K; Department of Physics, University of California at San Diego, La Jolla, California 92093, United States., Stamenic B; Nanofabrication Facility, Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, United States., John DD; Nanofabrication Facility, Department of Electrical and Computer Engineering, University of California, Santa Barbara, California 93106, United States., Averitt RD; Department of Physics, University of California at San Diego, La Jolla, California 92093, United States., Young AF; Department of Physics, University of California at Santa Barbara, Santa Barbara California 93106, United States. |
| Abstrakt: |
Free-space time domain THz spectroscopy accesses electrodynamic responses in a frequency regime ideally matched to interacting condensed matter systems. However, THz spectroscopy is challenging when samples are physically smaller than the diffraction limit of ∼0.5 mm, as is typical, for example, in van der Waals materials and heterostructures. Here, we present an on-chip, time-domain THz spectrometer based on semiconducting photoconductive switches with a bandwidth of 200 to 750 GHz. We measure the optical conductivity of a 7.5-μm wide NbN film across the superconducting transition, demonstrating spectroscopic signatures of the superconducting gap in a sample smaller than 2% of the Rayleigh diffraction limit. Our spectrometer features an interchangeable sample architecture, making it ideal for probing superconductivity, magnetism, and charge order in strongly correlated van der Waals materials. |
