ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
Since the real part of the refractive index of silica glass is smaller than unity in the soft x-ray region, it has been shown1–3 that silica-glass hollow-core fibers can transmit soft x rays. However, the transmittance for the silica fibers bent over a 90° were found to be lower than 0.1%. On the other hand, the multilayer metal coating technique has been developed in fabrication of flat mirrors for soft x-ray optics. If suitable multilayers can be deposited on the inner surface of a flexible hollow glass fiber, the transmittance for soft x rays of the fiber is expected to be considerably higher than that of noncoated hollow fibers. It is important to study the transmission characteristics of the hollow-core fiber whose inner surface is coated with metal. In the present study, we report the soft x-ray transmission characteristics of a Au-coated silica hollow-core fiber. The experimental setup is similar to that previously reported.4 The inner diameter of the Au-coated silica fiber used is about 2 mm and its length is 230 mm. The Au coating on the inner surface of the fiber was achieved by chemical plating. We measured the transmittances of the Au-coated silica fiber and a noncoated silica fiber with the same size. We measured the transmittance only for the bend angles smaller than 20°, because these relatively thick silica fibers were broken at about 25°. For a large bend angle (20°), the transmittances of the Au-coated fiber were one order of magnitude lower than that of the noncoated fiber in the short wavelength region below 45 A(ring). In the long wavelength region (longer than 60 A(ring)), the transmittance of the Au-coated fiber was higher than that of the noncoated fiber. At the oxygen K-shell absorption wavelength (23 A(ring)), the strong dip in transmission was observed in the noncoated silica fiber. However, there was not seen a strong dip in the Au-coated fiber. These results, the better transmittance for the long wavelengths, and no dip at 23 A(ring), show that the Au coating is effective in improving the soft x-ray reflectance in the inner surface of fibers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1140783
