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UCLA STROBE researchers show how a radiofrequency cavity can be used as an electron longitudinal lens in order to produce a highly magnified temporal replica of an ultrafast process, and, in combination with a deflecting cavity, enable streaked electron images of optical-frequency phenomena, taking advantage of the time-stretch concept.

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 STROBE team led by Prof. Miao, in collaboration with Argonne National Laboratory, implemented hybrid 3D X-ray microscopy by combining cryogenic hard X-ray ptychography and X-ray fluorescence microscopy. Here, STROBE’s advanced GENFIRE tomography algorithm was used to correlate high resolution ultrastructure mapping and elemental distributions in an unlabeled, frozen-hydrated green algae.

The ability to record large field of view images without a loss in spatial resolution is critical for many applications of imaging science. However, for most imaging techniques, an increase in field-of-view comes at the cost of decreased resolution. STROBE scientists at CU Boulder implemented a novel extension to ptychographic coherent diffractive imaging that permits simultaneous full-field imaging of multiple simultaneous locations on a sample, by illuminating it with spatially separated, interfering beams. This technique allows for large field-of-view imaging in amplitude and phase while maintaining diffraction-limited resolution, without an increase in collected data i.e. diffraction patterns acquired.

A STROBE team led by Simon Weiss implemented semiconductor-based voltage sensors as neuronal activity imaging probes. Unlike conventional voltage sensors, these nanosensors operating via the quantum confined Stark effect are highly sensitive, bright, and fast-responding. With further optimization, these nanosensors may enable single-particle detection and facilitate monitoring of neuronal signals at the nanoscale.

A STROBE team from UCLA, Berkeley and Boulder developed a nanoscale multimodal X-ray and electron microscopy framework that is applicable to a wide range of inhomogeneous samples with complex structural and chemical properties. Using an Allende meteorite as an example, we performed structural and chemical mapping to infer the mineral composition and its potential processes. This work opens a route to future microscopies of complex materials.

A STROBE team led by Prof. Waller, created a novel computational imaging autofocusing system for microscopes utilizing an of-the-shelf LED and a machine learning algorithm with optical physics knowledge incorporated into its design.