This week’s item is the PRL paper by Sandberg et al., “Lensless Diffractive Imaging Using Tabletop Coherent High-Harmonic Soft-X-Ray Beams” Phys. Rev. Lett. 99, 098103 (2007).
It is essentially a collaboration between JILA/Colorado groups of Henry Kapteyn and Margaret Murnane specializing in coherent soft x-ray tabletop sources, and John Miao’s UCLA group which specializes in lensless imaging, as well as folks from LBNL. The fact that these are very “soft” x-rays – wavelengths of 29 nm means that the spatial resolution is still rather limited (on the order of 100-200nm), compared to synchrotron sources such as ALS or APS, but on the flip side they can do measurements in their in-house lab, instead of relying on scarce synchrotron beamtime, which is a huge benefit. Traditional x-ray sources such as rotating anode and fixed tube can typically operate in hard x-ray range (8keV and higher), but the energy is also fixed and the sources are very incoherent.
I am looking forward to the times when the tabletop sources can become cheap and commonplace enough for other groups to do their characterization using these and other coherent x-ray scattering probes.