Broadband Time-Delay and Chirp Compensator for X-ray Pulses

A new type of aberration-corrected time-delay compensating monochromator (TDCM) for soft X-rays is presented. Composed of two identical reflection zone plates (RZPs) on spherical substrates and an intermediate flat mirror for band-pass selection, the TDCM can operate in a wide energy range of about +/- 20% around the design energy of 410 eV. Assuming a source size of 50 mu m and an angular acceptance of 1 mrad, the spectral resolving power may reach 6 x 10(2), at a pulse length as short as 4.3 femtoseconds (fs). In the case of mu m-sized sources, the resolution can be better than 0.1 eV and the sub-fs regime could become accessible. The overall transmission efficiency varies within (4.2-6.0)% across the energy range (310-510) eV. In the complementary mode, chirped-pulse compression works as well. Depending on the properties of the source, simulations predict an up to 9-fold reduction in pulse duration, whereas <= 50% of the peak intensity is maintained.