New Research: terahertz near field probes
Using terahertz (THz) electromagnetic waves for imaging has unveiled a number of scientific phenomena and has found practical applications in medicine and security. To surpass the diffraction limit for spatial resolution at THz frequencies, UCL researchers including Dr Oleg Mitrofanov in collaboration with Sandia National Laboratories (USA) recently developed THz near-field microscopy probes incorporating apertures as small as 3μm (1/100th of the wavelength at 1THz).
Transmission of THz waves through such sub-wavelength apertures is extremely week. However, within a close range from the aperture, the evanescent THz field was found to be significantly stronger than predicted by Bethe’s theory. Reported in Applied Physics Letters, the observed effect enabled the highest spatial resolution achieved to date for the sub-wavelength aperture THz time-domain imaging.
The developed THz probes open new horizons for THz near-field imaging, with applications in scientific investigations, THz device research, and THz spectroscopy.