Reconstruction of continuous soft X-ray spectra from spectrograms recorded using a transmission diffraction grating

An iteration method of the true continuous soft X-ray (SXR) and extreme ultraviolet (EUV) radiation spectra reconstruction from spectrograms, recorded with transmission diffraction gratings was developed. To verify the efficiency of the method we take an arbitrary radiation spectrum and mathematically transformed it into a diffraction pattern as if this pattern was created by the transmission grating in the registration plane. After that, the reverse task of the initial spectrum reconstruction is solved with the help of the developed iteration method. The reconstructed spectrum is compared with the initial one and this comparison shows that a small number of iterations are enough for the successful reconstruction of the spectrum. The results of application of the proposed method to the reconstruction of various spectrum shapes for the various aspect ratio gratings are considered. An important advantage of the proposed method (unlike the method previously known) is that it is applicable not only with the use of radiation linear detectors, but also with nonlinear detectors.