Janos Kirz developed X-ray imaging methods using zone plates. His joint technical account with David Attwood explains how diffraction replaces ordinary refraction in a small focusing optic. Replacing absorbing zones by zones that shift the wave phase can raise the focusing efficiency. Their account also connects finite illumination bandwidth to chromatic blurring: many zones improve focusing only if the incident X-rays occupy a sufficiently narrow range of wavelengths.[ref]
Zone Plates by Janos Kirz and David Attwood. Section 4.4, phase-shifting zones and the bandwidth condition N less than wavelength divided by spectral width
Portrait of Janos Kirz in 2025
. Via Wikimedia Commons; the linked file page provides image credits and usage information. Source.
Janos Kirz does not appear to be a widely recognized figure, term, or concept as of my last knowledge update in October 2023. If "Janos Kirz" refers to a recent development, individual, or term that has emerged after that date, I would not have information on it.
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