GENFIRE: A Generalized Fourier Iterative Reconstruction Algorithm for High-resolution 3D Imaging

September 5, 2017|

A STROBE team from the Miao group at UCLA implementated a powerful new tomographic algorithm, termed GENeralized Fourier Iterative REconstruction (GENFIRE), for high-resolution 3D reconstruction from a limited number of 2D projections. GENFIRE assembles a 3D Fourier grid with oversampling and then iterates between real and reciprocal space to search for a solution that is consistent with the measured data and physical constraints. This new algorithms has enabled many new imaging advances.

A. Pryor et al., “GENFIRE: A generalized Fourier iterative reconstruction algorithm for high-resolution 3D imaging”, Scientific Reports 7, 23: S1, (2017).

Sub-wavelength Coherent Diffractive Imaging Using a Tabletop High Harmonic Light Source

March 20, 2017|

Visible microscopes can produce crisp images with a spatial resolution on order of the illuminating wavelength, because of the availability of near-perfect lenses in this region of the spectrum. Extreme ultraviolet (EUV) and soft X-ray (SXR) light has wavelengths 10-100 times shorter than visible light: thus, it should be possible to design a powerful microscope that can image structures that are too small or too opaque to be seen with visible light. However, EUV/SXR lenses are very lossy and imperfect, limiting the advantage of using shorter wavelengths, and blurring the resulting images to >8 times the theoretical limit. Fortunately, new techniques pioneered by STROBE scientists Kapteyn, Murnane and Miao make it possible to build lensless microscopes illuminated by coherent laser-like beams — a capability that is revolutionizing X-ray imaging worldwide. Very recently, the Kapteyn-Murnane group at CU Boulder used tabletop EUV beams at a wavelength of 13nm to achieve sub-wavelength spatial resolution imaging at short wavelengths for the first time – essentially demonstrating the first near-perfect X-ray microscope. Moreover, because the EUV source produces exceedingly short, femtosecond (~10-15 sec), bursts of light, it can now be used to make stroboscopic movies to observe how the nanoworld functions. STROBE graduate student Dennis Gardner received the American Physical Society Division of Laser Science Thesis Award for this work.

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