Rensselaer Polytechnic Institute researchers have shown that terahertz rays can be used in conjunction with scanning near-field microscopy, according to a paper published in Applied Physics Letter.

The technique circumvents the usual “diffraction limit” on imaging methods, which restricts the resolution to the same order of magnitude as the wavelength of the radiation used.

By demonstrating a resolution of 150 nm using THz radiation of 150 microns, the researchers have been able to see below the diffraction limit by a factor of about a thousand.

This should make it possible to use biomedical THz imaging to view fundamental structures in the cell as well as for inspecting microscopic patterns in semiconductor chips.

Terahertz (THz) promises an alternative to techniques such as X-ray, magnetic-resonance and ultrasound imaging, being potentially cheaper, safer, more detailed and more penetrating. This makes it attractive for studying body tissue.

Chen H.-T., Kersting R. & Cho G. C. Terahertz imaging with nanometer resolution. Applied Physics Letters 83, 3009-3011 (2003)