The technique may also see biological agents through a sealed envelope or detect tumors without harmful radiation, say researchers at Rensselaer Polytechnic.

T-rays, named for the terahertz (THz) region of the electromagnetic spectrum, are defined by frequencies from 0.1 to 10 THz, just between infrared light and microwaves.

Objects at room temperature emit thermal energy in the THz range. T-ray systems provide both images and spectroscopic information about material composition, especially in chemical and biological species — something that X-rays may not be able to do. T-rays are also safer than X-rays for biological applications because photon energies are about 1 millionth that of X-ray photons.

Equipment based on T-ray technology may sense nanoscale objects as well as larger objects at distances exceeding 100 m, an important feature for remote sensing of explosives. T-rays could also bring label-free characterization of genetic material and help researchers understand the complex dynamics involved in protein folding.