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Supercontinuum breakthrough in fiber lasers
A manufacturer of fiber laser systems offers a supercontinuum breakthrough. Supercontinuum generation is considered to be based on intense laser beam light of one color that runs within a material, similar to glass, and spreads into a spectrum of colors. This fiber laser technology allows emitting a laser beam at colors required for such specific applications as bioimaging, optical communications, and essential investigations of materials.
Until recent times, two ways to produce a supercontinuum were distinguished. The first way includes the application of a thin optical fiber to concentrate a laser beam to high intensity over lengths of a few meters. The second way supposes the focus of a more powerful laser beam from an amplified laser system on the standard glass.
Limitations of conventional techniques
All these techniques have several disadvantages, for instance, large size, complexity, and high cost of applying a high-quality laser beam or the accurate and fragile tuning required to emit fiber laser light into an optical fiber that is only two thousandths of a millimeter in diameter. A team of researchers from Scotland presented a new fiber laser technology for reaching supercontinuum generation.
Novel approach to multicolored fiber lasers
Employing the novel technique, the researchers succeeded in producing a wide range of colors from a single laser system. The new fiber laser technology is based on the combination of a conventional laser system with a special, nonlinear crystal, leading to the design of a supercontinuum directly. Additionally, there is no need for either a high-power fiber laser or delicate coupling of laser beam light into thin optical fibers.
Operating principle with gallium phosphide crystal
The team claims that the operating principle is totally new: “our specially engineered gallium phosphide crystal creates a cascade effect.” The crystal is illuminated with a laser beam from an infrared laser system, and some of these beams are changed to visible green light. This, in its turn, produces more green laser beam light at a slightly longer wavelength, becoming first yellow, then orange, and working all the way out to the red.
Expanding the laser spectrum
It is possible to generate green laser beam light at longer and longer wavelengths from the weaker edges. The researchers plan to expand the spectrum of the fiber laser light and to make it more intense by optimizing the features of the crystal. Further improvements are required to detect whether the effect is specific to the special gallium phosphide crystal that is applied.