X-ray laser resonator for the kilo-electron-volt range

We have designed, constructed, and tested an x-ray laser resonator operating in the hard x-ray, keV energy region. This ring x-ray laser cavity is formed by four highly oriented pyrolytic graphite crystals. The crystals are set at the Bragg angles that allow for the complete 360° round trip of the 2.37 A, 5.23 keV Lα line of neodymium. In addition, we also present experimental data of a similar ring laser resonator that utilizes the Cr Kα, 5.41 keV, x-ray line to propagate through the four mirrors of the cavity. The specific properties of these x-ray laser resonator mirrors, including reflection losses and cavity arrangement, are presented.