Xi-Cheng Zhang has worked for nearly a decade to solve a scientific puzzle that many in the research community believed to be impossible: producing terahertz waves—a form of electromagnetic radiation in the far infrared frequency range—from liquid water.
Xi-Cheng Zhang has worked for nearly a decade to solve a scientific puzzle that many in the research community believed to be impossible: producing terahertz waves—a form of electromagnetic radiation in the far infrared frequency range—from liquid water.
Now, as reported in a paper published in Applied Physics Letters, researchers at the University of Rochester have “made the impossible, possible,” says Zhang, the M. Parker Givens Professor of Optics. “Figuring out how to generate terahertz waves from liquid water is a fundamental breakthrough because water is such an important element in the human body and on Earth.”
Terahertz waves have attracted increased attention recently because of their ability to nondestructively pass through solid objects, including those made of cloth, paper, wood, plastic, and ceramics, and produce images of the interiors of the objects. Additionally, the energy of a terahertz photon is weaker than an x-ray photon. Unlike x-rays, terahertz waves are non-ionizing—they do not have enough energy to remove an electron from an atom—so they do not have the same harmful effects on human tissue and DNA.
Because of these abilities, terahertz waves have unique applications in imaging and spectroscopy—everything from discovering bombs in suspicious packages, to identifying murals hidden beneath coats of paint, to detecting tooth decay.
Read more at University of Rochester
Image: Researchers use lasers to generate terahertz pulses via interaction with a target. In this case, the target was an extremely thin water film -- approximately 200 microns or about the thickness of two pieces of paper -- created using water suspended between two aluminum wires. (Credit: University of Rochester photo / Kaia Williams)
