Development of a Laser-Pumped X-Ray Laser with Full Spatial Coherence

抄録

A laser-pumped x-ray laser with full spatial coherence has been developed for the first time. This x-ray laser has a wavelength of 13.9 nm and a beam divergence of 0.2 mrad. In the experiment, a seeding light from the first laser medium was amplified in the second medium, which worked as an active spatial filter. The observed beam divergence was close to the diffraction limited value within a factor of two. The seeding light was amplified in the second medium without refraction influence. The gain region of the second medium was far away from the target surface compared with that of the first medium, and was located in a region of considerably low density. From the measurement of visibility, it was found that the spatial coherent length was longer than the beam diameter. This means that this x-ray laser beam has full spatial coherence.