While diamond lasers have been around for a number of years, they have not been powerful enough to cut through steel until now. Since the recent improvement of CVD (Chemical Vapor Deposition) fabrication methods for diamonds, making them larger and purer, researchers from the Fraunhofer Institute for Applied Optics in Germany and the MQ Photonics Research Centre in Australia developed a diamond laser 20x more powerful than anything thus far.
With 380 Watts at a wavelength of 1240nm, the new laser makes use of Raman conversion to shift wavelengths of light that are long enough to effectively be absorbed by steel. If the wavelength is shorter and protons pass through or get reflected, the diamond won’t deposit enough energy for cutting. A longer wavelength translates to less interference and reduced risk to humans, as there is less damage done to the retina.
Through the Raman conversion, scientists were able to highlight the efficiency of circular polarization pumping, while also making it easier to achieve high-power optical isolation between the Raman laser and the pump.
“We achieved continuous-wave average power of 154 W with a conversion efficiency of 50.5 percent limited by backward-amplified light in the fiber laser,” the scientists said. “In order to prove further scalability, we achieved a maximum steady-state Raman-shifted output of 381 W with 61 percent conversion efficiency and excellent beam quality using 10 ms pump pulses, approximately a thousand times longer than the transient thermal time-constant.”
High-power diamond lasers are equipped for applications that require beaming power over long distances, such as optical communications in space, laser ranging, and the tracking and removal of space debris.
“Diamond crystals seem to naturally fit to high power fiber lasers. It's interesting to see that such a development is now possible and I'm sure much exciting research will follow,” said Thomas Schreiber, group leader for the fiber laser research at the Fraunhofer IOF Jena, Germany.
Diamond lasers have the potential to unveil more than just cutting and machining technologies, including possible diamond-based x-ray lasers, especially as costs of CVD diamonds continue to decline and its qualities rise.
Source: ExtremeTech
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