X-ray flux enhancement in thin-film waveguides using resonant beam couplers

We present experimental evidence for achieving significant x-ray flux enhancement by coupling a highly collimated and monochromatic synchrotron x-ray beam into a Si/polyimide/${\mathrm{SiO}}_2$ thin-film waveguide. The observed 20-fold flux increase agrees with theoretical predictions and was limited only by absorption of the 1 Å x rays in the waveguide structure.