6,849 research outputs found
Light-sheet microscopy: a tutorial
This paper is intended to give a comprehensive review of light-sheet (LS) microscopy from an optics perspective. As such, emphasis is placed on the advantages that LS microscope configurations present, given the degree of freedom gained by uncoupling the excitation and detection arms. The new imaging properties are first highlighted in terms of optical parameters and how these have enabled several biomedical applications. Then, the basics are presented for understanding how a LS microscope works. This is followed by a presentation of a tutorial for LS microscope designs, each working at different resolutions and for different applications. Then, based on a numerical Fourier analysis and given the multiple possibilities for generating the LS in the microscope (using Gaussian, Bessel, and Airy beams in the linear and nonlinear regimes), a systematic comparison of their optical performance is presented. Finally, based on advances in optics and photonics, the novel optical implementations possible in a LS microscope are highlighted.Peer ReviewedPostprint (published version
Superresolution Microscopy of the Volume Phase Transition of pNIPAM Microgels
Hierarchical polymer structures such as pNIPAM microgels have been
extensively studied for their ability to undergo significant structural and
physical transformations that can be controlled by external stimuli such as
temperature, pH or solvent composition. However, direct three-dimensional
visualization of individual particles in situ have so far been hindered by
insufficient resolution, with optical microscopy, or contrast, with electron
microscopy. In recent years superresolution microscopy techniques have emerged
that in principle can provide nanoscopic optical resolution. Here we report on
the in-situ superresolution microscopy of dye-labeled submicron sized pNIPAM
microgels revealing the internal microstructure during swelling and collapse of
individual particles. Using direct STochastic Optical Reconstruction Microscopy
(dSTORM) we demonstrate a lateral optical resolution of 30nm and an axial
resolution of 60nm.Comment: 7 pages, 5 figure
Near-field microscopy with a scanning nitrogen-vacancy color center in a diamond nanocrystal: A brief review
We review our recent developments of near-field scanning optical microscopy
(NSOM) that uses an active tip made of a single fluorescent nanodiamond (ND)
grafted onto the apex of a substrate fiber tip. The ND hosting a limited number
of nitrogen-vacancy (NV) color centers, such a tip is a scanning quantum source
of light. The method for preparing the ND-based tips and their basic properties
are summarized. Then we discuss theoretically the concept of spatial resolution
that is achievable in this special NSOM configuration and find it to be only
limited by the scan height over the imaged system, in contrast with the
standard aperture-tip NSOM whose resolution depends critically on both the scan
height and aperture diameter. Finally, we describe a scheme we have introduced
recently for high-resolution imaging of nanoplasmonic structures with ND-based
tips that is capable of approaching the ultimate resolution anticipated by
theory.Comment: AD, AC, OM, MB and SH wish to dedicate this brief review article to
their co-author and colleague Yannick Sonnefraud who passed away in September
2014. Yannick initiated this research in 200
Real-Time analysis and visualization for single-molecule based super-resolution microscopy
Accurate multidimensional localization of isolated fluorescent emitters is a time consuming process in single-molecule based super-resolution microscopy. We demonstrate a functional method for real-time reconstruction with automatic feedback control, without compromising the localization accuracy. Compatible with high frame rates of EM-CCD cameras, it relies on a wavelet segmentation algorithm, together with a mix of CPU/GPU implementation. A combination with Gaussian fitting allows direct access to 3D localization. Automatic feedback control ensures optimal molecule density throughout the acquisition process. With this method, we significantly improve the efficiency and feasibility of localization-based super-resolution microscopy
Cosmic Rays from the Knee to the Highest Energies
This review summarizes recent developments in the understanding of
high-energy cosmic rays. It focuses on galactic and presumably extragalactic
particles in the energy range from the knee (10^15 eV) up to the highest
energies observed (>10^20 eV). Emphasis is put on observational results, their
interpretation, and the global picture of cosmic rays that has emerged during
the last decade.Comment: Invited review, submitted to Progress in Particle and Nuclear Physic
Position Reconstruction in Drift Chambers operated with Xe, CO2 (15%)
We present measurements of position and angular resolution of drift chambers
operated with a Xe,CO(15%) mixture. The results are compared to Monte Carlo
simulations and important systematic effects, in particular the dispersive
nature of the absorption of transition radiation and non-linearities, are
discussed. The measurements were carried out with prototype drift chambers of
the ALICE Transition Radiation Detector, but our findings can be generalized to
other drift chambers with similar geometry, where the electron drift is
perpendicular to the wire planes.Comment: 30 pages, 18 figure
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