Like conventional glass, synthetic quartz glass consists of silicon dioxide. However, it stands out from the crowd because it is bubble-free and extremely pure. This gives it up to 90 percent light transmission from the ultraviolet to the infrared wavelength range. Ideal for a laser light beam that even the smallest impurities can interfere with. "Standard glass can't compete with that," emphasizes Peter Bauer, Product Manager Specialty Fiber at Heraeus Conamic. "At the high powers transmitted by lasers today, normal glass would absorb too much energy compared to fused silica and be destroyed." In addition, fused silica fibers are break- and tear-resistant as well as extremely flexible. The last point pays off in surgeries to reach parts of the human body that are difficult to access.
The flexibility of the specialty fibers is an advantage, for example, in the laser treatment of kidney, gall or bladder stones, because the extremely small bending radius allows penetration into the very narrow channels of these organs. In addition, an even more compact infrared laser with a wavelength of 1,900 nanometers (nm) has also recently been used here instead of the earlier much larger and more inefficient devices with 2,100 nm. Another example is green laser light at 532 nm. It is ideal for treating growths on the prostate. The red blood cells absorb the green light and thus no bleeding occurs. In recent years, the gentle treatment of varicose veins with red laser light has also become increasingly popular. The radiation of the laser catheter with 633 nm enables the surgeon to seal the entire varicose vein with the catheter. What remains, if anything, is a small bruise.