X-Rays: Optical Elements

X-ray diffraction provided the first means to deflect x-rays by a substantial amount. It established that the wavelength was in the 1 A range, and it became possible to deduce the structure of a crystal with atomic resolution. The success of x-ray diffraction has two important foundations. First, the small scattering amplitudes from individual atoms in a periodic structure add in phase in certain directions. The second important feature of x-ray diffraction is the reduction of radiation damage. Imaging of nonperiodic objects with diffraction-limited or atomic resolution is still a challenge for the future. This entry discusses some of the features associated with x-ray diffraction.