{"id":299372,"date":"2018-02-23T13:20:40","date_gmt":"2018-02-23T18:20:40","guid":{"rendered":"http:\/\/www.rochester.edu\/newscenter\/?p=299372"},"modified":"2018-03-08T11:46:53","modified_gmt":"2018-03-08T16:46:53","slug":"laser-focus-super-water-repellent-metals-299372","status":"publish","type":"post","link":"https:\/\/www.rochester.edu\/newscenter\/laser-focus-super-water-repellent-metals-299372\/","title":{"rendered":"A laser focus on super water-repellent metals"},"content":{"rendered":"

In a laboratory at the University of Rochester, researchers are using lasers to change the surface of metals in incredible ways, such as making them super water-repellent without the use of special coatings, paints, or solvents.<\/p>\n

The commercial applications of the technology range from de-icing of commercial airplanes and large trucks, to rust and corrosion prevention of exposed metal surfaces, to cleaner, anti-microbial surfaces for surgical and medical facilities.<\/p>\n

But to make the technology commercially viable, the lasers must become much more powerful.<\/p>\n

John Marciante,<\/a> an associate professor of optics, and the University\u2019s Institute of Optics,<\/a> is working with venture capital-backed technology company, FemtoRoc Corp., to develop those more powerful lasers. His contract with the company, expected to take six years, has a research budget estimated at $10 million.<\/p>\n

\u201cWhat they [FemtoRoc] need is a high-powered, ultra-fast, femtosecond-class laser system with average power measured in kilowatts, rather than the 10\u2019s of watts now commercially available,\u201d says Marciante. \u201cSo, we need to scale up by over a factor of 10.\u201d<\/p>\n

\u201cIt\u2019s a very ambitious undertaking.\u201d<\/p>\n

The proprietary, super-hydrophobic technology uses lasers to create an intricate pattern of micro and nanoscale structures, giving the treated metal surfaces a new set of physical properties.<\/p>\n

In 2015, Chunlei Guo<\/a>, a professor of optics, and Anatoliy Vorobyev, a senior scientist at the Institute of Optics, described the extremely powerful, but ultra-short laser pulses they used to permanently change the surface of metals.<\/p>\n

Guo and Vorobyev have successfully used this technique to create not only metal surfaces that are extremely water repellent<\/a>, but ones that attract water as well. Guo\u2019s laboratory has also created a process to treat metal surfaces to absorb virtually all wavelengths of ambient light and which has a wide array of commercial applications, including thin, ultra-efficient solar cells.<\/p>\n

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However, it takes about an hour for Guo\u2019s laboratory to pattern a 1-inch-by-1-inch metal sample using commercially available, low-powered lasers. More powerful, ultra-fast femtosecond laser pulses are needed to speed up the process to make the technology commercially viable.<\/p>\n

To develop the lasers, Marciante\u2019s laboratory, which specializes in developing advanced, high-power, fiber lasers, will need to address two main challenges.<\/p>\n

One is that laser beams are usually confined in conventionally designed optical fibers, which tend to be very small in core diameter. In scaling up the laser power, too much light becomes concentrated in the fiber\u2019s core, and nonlinear properties proliferate, causing the laser beam to broaden or become modulated.<\/p>\n

\u201cWhen you try to compress the beam to a short pulse, there\u2019s a lot of energy that doesn\u2019t fit in that pulse,\u201d Marciante explains. \u201cThe usable power spreads out, or does not focus where you want it to.\u201d<\/p>\n

The second challenge is overheating. \u201cYou\u2019re pumping the laser beam at one energy level, at one end, and then extracting it at a lower energy level, at the other end, and no process is 100 percent thermally efficient.\u00a0 So that extra energy ends up in the fiber. The fiber can get very hot, even to the point of melting,\u201d Marciante says.<\/p>\n

In addition to the research done by his own team, Marciante will leverage a network of veteran researchers in the United States and abroad and bring in third party vendors with proven fiber design and manufacturing capabilities.<\/p>\n

Marciante\u2019s research has already yielded the following results:<\/p>\n