Phys.org March 25, 2024 Despite real-time femtophotography advantages over conventional multi-shot approaches, existing techniques confront restricted imaging speed or degraded data quality by the deployed optoelectronic devices application scope, acquisition accuracy, and hindered by the limitations in the acquirable information imposed by the sensing models. An international team of researchers (Canada, France) overcame these challenges by developing swept coded aperture real-time femtophotography (SCARF). This enables all-optical ultrafast sweeping of a static coded aperture during the recording of an ultrafast event, bringing full sequence encoding of up to 156.3 THz to every pixel on a CCD camera. They demonstrated SCARF’s single-shot ultrafast […]
Category Archives: Imaging technology
Holographic message encoded in simple plastic
Phys.org March 18, 2024 Researchers in Austria produced a sub-terahertz holographic image of a two-dimensional 576-bit data code using a diffractive phase-plate element. The phase plate was designed to encode a focused image of the data code into a phase modulation profile. The complex phase plate structure is fabricated from polylactic acid using fused deposition modeling, a common three-dimensional-printing technique. The simplified optical setup, consisted of a 0.14 THz diverging source, the holographic phase plate, and a scanning detector, without the need for additional optical elements. The information stored in the data code was an example of a cryptographic private […]
Projection mapping leaves the darkness behind
Phys.org March 18, 2024 Projection mapping (PM) typically requires a dark environment to achieve high-quality projections, limiting its practicality. Researchers in Japan overcame this limitation by replacing conventional room lighting with heterogeneous projectors. These projectors replicated environmental lighting by selectively illuminating the scene, excluding the projection target. They developed distributed projector optimization framework designed to effectively replicate environmental lighting and incorporated a large-aperture projector, in addition to standard projectors, to reduce high-luminance emitted rays and hard shadows. To validate their approach, they conducted a series of quantitative and qualitative experiments. They successfully demonstrated that their projector-based lighting system significantly enhanced […]
Building images photon-by-photon to increase the information content provided by microscopes
Phys.org February 6, 2024 A flawless recording of single-photon spatiotemporal information poses significant challenges for the microscope data acquisition (DAQ) system. An international team of researchers (Italy, Switzerland) has presented a DAQ module based on the digital frequency domain principle, able to record essential spatial and temporal features of photons. They used the module to extend the capabilities of established imaging techniques based on single-photon avalanche diode (SPAD) array detectors. They used the module to introduce a robust multispecies approach encoding the fluorophore excitation spectra in the time domain. By combining time-resolved stimulated emission depletion microscopy with image scanning microscopy, […]
A new wavelength of scientific exploration with single-photon detectors
Phys.org January 31, 2024 Superconducting nanowire single-photon detectors (SNSPDs) are a mature photon-counting technology as demonstrated by their figures of merit such as high detection efficiencies and very low dark count rates. However, scaling SNSPDs to large array sizes for mid-infrared applications requires sophisticated readout architectures in addition to superconducting materials development. Researchers at NIST, Boulder, Colorado, developed an SNSPD array design that combined a thermally coupled row-column multiplexing architecture with a thermally coupled time-of-flight transmission line for mid-infrared applications. It required only six cables and could be scaled to larger array sizes. The demonstration of a 64-pixel array showed […]
Clear holographic imaging in turbulent environments
Phys.org October 30, 2023 The existing deep-learning methods for holographic imaging often depend solely on the specific condition based on the given data distributions. One critical problem is how to guarantee the alignment between any given downstream tasks and pretrained models. Researchers in China analyzed the physical mechanism of image degradation caused by turbulence and proposed a swin transformer-based method, termed train-with-coherence-swin (TWC-Swin) transformer, which used spatial coherence (SC) as an adaptable physical prior information to precisely align image restoration tasks in the arbitrary turbulent scene. They designed light-processing system (LPR) which enabled manipulation of SC and simulation of any […]
Superlensing without a super lens: Physicists boost microscopes beyond limits
Phys.org October 18, 2023 Imaging with resolutions much below the wavelength λ remains challenging at lower frequencies, where exponentially decaying evanescent waves are generally measured using a tip or antenna close to an object. Such approaches are often problematic because probes can perturb the near-field itself. Researchers in Australia have demonstrated that information encoded in evanescent waves can be probed further than previously thought, by reconstructing truthful images of the near-field through selective amplification of evanescent waves like a virtual superlens that images the near field without perturbing it. They quantified trade-offs between noise and measurement distance, experimentally demonstrated reconstruction […]
Unveiling the invisible: A bioinspired CMOS-integrated polarization imaging sensor
Phys.org September 18, 2023 Chip-integrated, fast, cost-effective, and accurate full-Stokes polarimetric imaging sensors are highly desirable in many applications, but they remain elusive due to fundamental material limitations. Researchers at the State University of Arizona have developed a chip-integrated Metasurface-based Full-Stokes Polarimetric Imaging sensor (MetaPolarIm) by integrating an ultrathin (~600 nm) metasurface polarization filter array (MPFA) onto a visible imaging sensor with CMOS compatible fabrication processes. The MPFA has broadband dielectric-metal hybrid chiral metasurfaces and double-layer nanograting polarizers. This chip-integrated polarimetric imaging sensor enabled single-shot full-Stokes imaging (speed limited by the CMOS imager) with the most compact form factor, recorded high […]
Wifi can read through walls
Science Daily September 11, 2023 Imaging still scenery with Wi-Fi is considerably challenging due to the lack of motion. The interaction of object edges with the incoming wave, dictated by the Geometrical Theory of Diffraction and the resulting Keller cones, presents new possibilities for imaging with WiFi via edge tracing. Researchers at UC Santa Barbara used the Geometrical Theory of Diffraction and the corresponding Keller cones to trace edges of the objects. They considered the impact of parameters such as curvature of a soft edge, edge orientation, distance to the receiver grid, transmitter location, and other parameters on edge-based WiFi […]
Scientists continue to push the boundaries of imaging techniques and reveal the mysterious world of molecules
Nanowerk August 29, 2023 Researchers in Czech Republic have experimentally confirmed the correctness of a decades-old theory that assumed a non-uniform distribution of electron density in aromatic molecules, a phenomenon that significantly affects the physicochemical properties of molecules and their interactions. They presented the resolution of the π-hole on a single molecule which supports the theoretical prediction of its existence. Experimental measurements supported by theoretical calculations showed the importance of π-holes in the process of adsorption of molecules on solid-state surfaces. According to the researchers better knowledge of the distribution of the electron charge will help the scientific community to […]