Soft X-rays in the Water Window

See allHide authors and affiliations

Science  03 Oct 2003:
Vol. 302, Issue 5642, pp. 13
DOI: 10.1126/science.302.5642.13d

The generation of coherent soft x-rays in the water window (wavelengths near 4 nanometers), a region transparent to water but absorbing to carbon, is the desired goal in developing table-top coherent x-ray sources for applications in biological imaging. Ionizing gases with high-intensity pulses of infrared light can result in difficult-to-control soft x-ray emission through high-harmonic generation. Gibson et al. (p. 95) show that the control problems can be circumvented by using a spatially modulated waveguide fiber filled with neon gas. In particular, they demonstrate enhanced generation of soft x-rays around 4.4 nanometers whereby the spatially periodic waveguide enables quasi-phase matching of the x-rays generated at higher harmonics.

Navigate This Article