Methodology for optimal in situ alignment and setting of bendable optics for diffraction-limited focusing of soft x-rays

摘要

We demonstrate a comprehensive and broadly applicable methodology for the optimal in situ configuration of bendablesoft x-ray Kirkpatrick-Baez mirrors. The mirrors used for this application are preset at the ALS Optical MetrologyLaboratory prior to beamline installation. The in situ methodology consists of a new technique for simultaneously settingthe height and pitch angle of each mirror. The benders of both mirrors were then optimally tuned in order to minimizeray aberrations to a level below the diffraction-limited beam waist size of 200 nm (horizontal) × 100 nm (vertical). Afterapplying this methodology, we measured a beam waist size of 290 nm (horizontal) × 130 nm (vertical) with 1 nm lightusing the Foucault knife-edge test. We also discuss the utility of using a grating-based lateral shearing interferometerwith quantitative wavefront feedback for further improvement of bendable optics.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.