X ray Wavefront Hartmann Sensor

We report an experimental demonstration of wavefront analysis via the Hartmann technique in the EUV. The reference wave front needed to calibrate the sensor was generated by spatially filtering a focused undulator beam with 1.7 (0.6) μm pinhole. To fully characterize the sensor, accuracy and sensitivity measurements were performed. The incident beam’s wavelength was varied between 7 and 25 nm. Measurements of accuracy better than λEUV=120 (0.11 nm) were obtained λEUV=13.4 nm. The wavefront of the spatially unfiltered incident beam was also measured.