Search results for "Ion microscopy"
showing 10 items of 91 documents
Two-photon light-sheet microscopy for high-speed whole-brain functional imaging of zebrafish neuronal physiology and pathology
2020
We present the development of a custom-made two-photon light-sheet microscope optimized for high-speed (5 Hz) volumetric imaging of zebrafish larval brain for the analysis of neuronal physiological and pathological activity. High-speed volumetric two-photon light-sheet microscopy is challenging to achieve, due to constrains on the signal-to-noise ratio. To maximize this parameter, we optimized our setup for high peak power of excitation light, while finely controlling its polarization, and we implemented remote scanning of the focal plane to record without disturbing the sample. Two-photon illumination is advantageous for zebrafish larva studies since infra-red excitation does not induce a …
Dispersion management in two-photon microscopy by using diffractive optical elements.
2013
We demonstrate efficient generation of wide-field fluorescence signals in two-photon microscopy exploiting diffractive optical elements and short pulses by using a dispersion-compensated beam delivery optics module. Computer-generated holograms are codified onto a phase-only spatial light modulator, which allows for arbitrary single-shot patterning of the sample. Spatiotemporal shaping of the pulse is mandatory to overcome spatial chirp and pulse-front tilt effects that spread both in space and time the irradiance patterns, thus limiting not only the spatial resolution but also the signal-to-noise ratio in two-photon microscopy. By using a multipass amplifier delivering 30 fs, 0.8 mJ pulses…
Superresolution imaging of biological nanostructures by spectral precision distance microscopy
2011
For the improved understanding of biological systems on the nanoscale, it is necessary to enhance the resolution of light microscopy in the visible wavelength range beyond the limits of conventional epifluorescence microscopy (optical resolution of about 200 nm laterally, 600 nm axially). Recently, various far-field methods have been developed allowing a substantial increase of resolution ("superresolution microscopy", or "lightoptical nanoscopy"). This opens an avenue to 'nano-image' intact and even living cells, as well as other biostructures like viruses, down to the molecular detail. Thus, it is possible to combine light optical spatial nanoscale information with ultrastructure analyses…
Automatic fringe pattern enhancement using truly adaptive period-guided bidimensional empirical mode decomposition.
2020
Fringe patterns encode the information about the result of a measurement performed via widely used optical full-field testing methods, e.g., interferometry, digital holographic microscopy, moiré techniques, structured illumination etc. Affected by the optical setup, changing environment and the sample itself fringe patterns are often corrupted with substantial noise, strong and uneven background illumination and exhibit low contrast. Fringe pattern enhancement, i.e., noise minimization and background term removal, at the pre-processing stage prior to the phase map calculation (for the measurement result decoding) is therefore essential to minimize the jeopardizing effect the mentioned error…
Investigating spintronics thin film systems with synchrotron radiation
2009
Abstract Spintronics is a research field involving a wide variety of different magnetic materials. Synchrotron radiation in the VUV and soft X-ray regime is ideally suited to investigate the relationships between magnetic properties and electronic structure of spintronics thin film stacks. Complex layered structures and nanomagnets are the main building blocks for current and future spintronics applications. In this contribution we describe the study of spintronics model systems with respect to the static and dynamic behavior with an emphasis on interfaces.
Fast whole-brain imaging of seizures in zebrafish larvae by two-photon light-sheet microscopy
2022
Light-sheet fluorescence microscopy (LSFM) enables real-time whole-brain functional imaging in zebrafish larvae. Conventional one photon LSFM can however induce undesirable visual stimulation due to the use of visible excitation light. The use of two-photon (2P) excitation, employing near-infrared invisible light, provides unbiased investigation of neuronal circuit dynamics. However, due to the low efficiency of the 2P absorption process, the imaging speed of this technique is typically limited by the signal-to-noise-ratio. Here, we describe a 2P LSFM setup designed for non-invasive imaging that enables quintuplicating state-of-the-art volumetric acquisition rate of the larval zebrafish bra…
Contrôle de nano-antennes optiques par une commande électrique : tuner plasmonique et transduction
2011
Optical nano-antennae are the new class of components to control light/matterinteraction at the nanoscale. These devices are operating in the visible to near infraredpart of the spectrum. The properties of these nano objects are controlled by theform, the size and the material.In the radio frequency domain, the tuner changes dynamically the operatingwavelength of the antenna. In this thesis work, we search to transfer this conceptto the nanoscale. The principle is to change the load impedance of the antenna, i.e.changing the optical index of the dielectric medium around the nano-object. Forthat we used anisotropic liquid cristal molecules. The value of the optical index iscontrolled by appl…
Multi-analytical study of the medieval wall paintings from the rupestrian church Grotta del Crocifisso at Lentini (eastern Sicily): new evidence of t…
2022
AbstractThis study presents the results of the examination and characterisation of the wall paintings that decorate the rupestrian church named Grotta del Crocifisso, which is located in the territory of Lentini (eastern Sicily, few tens of kilometres from Catania and Syracuse). The earliest mural paintings in the church date back to the twelfth century AD. A multi-analytical approach was adopted for the characterisation of stone materials, secondary degradation products, and pigments. For this purpose, the following techniques were used: reflected light microscopy (RLM), polarised light microscopy on thin sections (PLM), X-ray powder diffraction (XRPD), mercury intrusion porosimetry (MIP),…
Sidelobe decline in single-photon 4Pi microscopy by Toraldo rings.
2003
We demonstrate theoretically the feasibility of single-photon 4Pi-confocal microscopy. By inserting a pair of properly designed multi-ring phase-only pupil filters in the illumination path of a 4Pi microscope the height of the sidelobes of the point spread function substantially reduced, so that there is no ambiguity in the 3D image. Then, an axial resolution up to four times higher than that of single-photon confocal microscope can be effectively achieved.
Thin film growth into the ion track structures in polyimide by atomic layer deposition
2017
Abstract High-aspect ratio porous structures with controllable pore diameters and without a stiff substrate can be fabricated using the ion track technique. Atomic layer deposition is an ideal technique for depositing thin films and functional surfaces on complicated 3D structures due to the high conformality of the films. In this work, we studied Al2O3 and TiO2 films grown by ALD on pristine polyimide (Kapton HN) membranes as well as polyimide membranes etched in sodium hypochlorite (NaOCl) and boric acid (BO3) solution by means of RBS, PIXE, SEM-EDX and helium ion microcopy (HIM). The focus was on the first ALD growth cycles. The areal density of Al2O3 film in the 400 cycle sample was det…