Near-field time-resolved imaging with far-infrared dipole sources

Summary form only given. High-resolution imaging beyond the diffraction limit of conventional optical systems can be achieved in near-field microscopy, which has been demonstrated in various spectral regions. While implementations using evanescent fields generally suffer from extremely low signal intensities, schemes for high-efficiency near-field imaging have recently been proposed and demonstrated. We explore a similar approach for near-field imaging with terahertz (THz) waves. In singular-electric field THz emitters, the spatial extent of the THz radiation source is considerably smaller than the wavelength. Scanning an object in the near-field region of the emitter allows us to attain subwavelength resolution with a very high collection efficiency.