Apr-09
107
Avantes
www.avantes.com
UV/VIS Fiber attenuation
VIS/NIR Fiber Attenuation
Solarization Resistant Fibers for Deep UV applications
Most spectroscopic applications with fiber optics have been restricted to wavelength ranges above
230nm, because standard silica fibers with an undoped core and fluorine doped cladding are
frequently damaged by exposure to deep-UV light (below 230nm). This solarization effect is induced
by the formation of "color centers" with an absorbance band of 214 nm. These color centers are
formed when impurities (like Cl) exist in the core fiber material and form unbound electron pairs on
the Si atom, which are affected by the deep UV radiation.
Not long ago, solarization resistant fibers, which were hydrogen loaded, were developed (UVI). The
disadvantage for these fibers is the limitation on smaller fiber diameters and limited lifetime,
caused by the H
2
outgass from the fiber.
Recently, with the availability of a modified core preform, a new fiber became available (UVM). This
fiber provides long-term stability at 30-40% transmission (for 215nm). All fiber optic probes, cables
and bundles with core diameters of 100µm, 200m, 400m and 600µm can be delivered with
solarization resistant fibers. All assemblies, made by us, are pre-solarized for an 8-hrs period, to
have a constant transmission of 30-40% @ 215nm.
