A device for use with a source of radiation to provide a THz emission image representing a sample. The device comprises a substrate, a metallic probe having a tip adjacent to the substrate surface and a source of AC bias coupled between the probe tip and substrate. Radiation generated by the source of radiation is incident on the substrate surface in the vicinity of the probe tip and generates THz emission based at least on the AC bias coupled between the probe tip and substrate. A method for providing a THz emission image representing a sample is also provided.