High-resolution Fourier transform x-ray spectroscopy

Fourier transform spectroscopy was extended to the x-ray region using an intensity correlation technique and a separate crystal design of an x-ray Michelson interferometer capable of a large path difference. A demonstration was presented measuring the bandwidth of Si 0 6 14 back diffraction as narrow as 12.8 attometers at a wavelength of 71.3 pm. Insensitivity of the resolution to the crystal perfection would open up ultrahigh-resolution spectroscopy beyond 10(-9). (C) 2003 American Institute of Physics.