Laser-Modified Metals Allow for Imaging Diseases on the Molecular Level

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Ultra-absorbent laser-treated black metals could allow for the imaging of disease pathogens on the molecular level. Image: University of Rochester.

Modifying the surface of metals using a femtosecond laser process could potentially enable the imaging of disease pathogens, according to researchers at the University of Rochester (New York). Using the group's previous research as a foundation, Professor Chunlei Guo and research assistant Anatoliy Vorobyev have made a breakthrough that could lead to better diagnostic methods without tissue damage.Back in 2006, Guo's group nabbed headlines through the development of an innovative technology involving femtosecond laser pulses. The group found that by blasting the surface of various metals with an ultrabrief, ultraintense laser pulse, they could dramatically modify the material's reflective properties. Owing to the extreme force applied in less than one quadrillionth of a second, the process prompted such metals as aluminum, gold, and tungsten to turn black.In a new discovery, Guo and his colleagues have realized that the laser-modified metals can actually absorb terahertz radiation. Because the laser technique leaves the treated metal 30 times more light absorbent, according to the researchers, the material can detect electromagnetic radiation with frequencies in the terahertz range, which traditional materials rarely, if ever, are able to do. This capability paves the way for exciting rotational and vibrational states of organic compounds, such as pathogens, the group states."When we turned metals black, we knew that they became highly absorptive in the visible wavelength range because the altered metals appear pitch black to the eye," Guo says. "Here, we experimentally demonstrated that the enhanced absorption extends well into the far infrared and terahertz frequencies."