Search results for "Lens"
showing 10 items of 948 documents
Systematic Comparison of Epidemic and Non-Epidemic Carbapenem Resistant Klebsiella pneumoniae Strains
2021
Over the past few decades, extensively drug resistant (XDR) resistant Klebsiella pneumoniae has become a notable burden to healthcare all over the world. Especially carbapenemase-producing strains are problematic due to their capability to withstand even last resort antibiotics. Some sequence types (STs) of K. pneumoniae are significantly more prevalent in hospital settings in comparison to other equally resistant strains. This provokes the question whether or not there are phenotypic characteristics that may render certain K. pneumoniae more suitable for epidemic dispersal between patients, hospitals, and different environments. In this study, we selected seven epidemic and non-epidemic ca…
A MEMS array-type Mirau interferometer for swept-source OCT imaging with applications in dermatology
2017
In the frame the European project VIAMOS (www.viamos.eu) we developed a microsystem based on Mirau interferometry and applied for optical coherence tomography (OCT) imaging of living tissues. The objective is to benefit from advanced MOEMS technologies, enabling a new generation of miniature and low-cost instruments using the concept of the swept-source OCT (SS-OCT) microsystem based on spectrally tuned Mirau interferometry, into which a doublet of microlens matrices (4×4) and a wafer of movable reference mirrors are included, building the active Mirau interferometer.
Examining the utility of pinhole-type screens for lightfield display
2021
The use of microlens arrays for lightfield display has the drawback of providing images with strong chromatic aliasing. To overcome this problem, pinhole-type lightfield monitors are proposed. This paper is devoted to evaluating the capability for such lightfield monitors to offer the user a convincing 3D experience with images with enough brightness and continuous aspect. Thus, we have designed a psychophysical test specifically adapted for lightfield monitors, which allowed us to confirm the usability of pinhole-type monitors.
Self-imaging properties of a periodic microlens array: versatile array illuminator realization
1994
Abstract The general features of the wavefield diffracted by a microlens array are described. The transversal periodicity of both a refractive and a diffractive periodic microlens array allows to obtain a set of replicas of the focal intensity distribution along the optical axis of the system, with different multiplicity. The result is applied for implementing a versatile optical array illuminator, with a variable density of bright spots at the output plane. Some experimental results of the procedure are shown.
Enhanced viewing-angle integral imaging by multiple-axis telecentric relay system
2009
One of the main limitations of integral imaging is the narrow viewing angle. This drawback comes from the limited field of view of microlenses during the pickup and display. We propose a novel all-optical technique which allows the substantial increase of the field of view of any microlens and therefore of the viewing angle of integral-imaging displays.
Micro-optical components for parallel optical networks
2002
Key components for parallel optical links are fabricated cost-effectively using LIGA technology. Multifiber ferrules and mechanical splices, 1/spl times/2 and 4/spl times/4 single-mode matrix switches and micro lens arrays with passive alignment structures are presented.
Time-multiplexing Integral Microscopy
2014
Conventional microscopes do not capture the 3D information of thick specimens. In order to avoid this limitation Integral Microscopy was proposed. An integral microscope is implemented by inserting a microlens array between the microscope objective and the camera sensor. Although this device captures multiperspective information of the specimen, the small number of microlenses limits the lateral resolution. In this paper we propose to improve the resolution by time multiplexing. Specifically, we propose an electrically addressable device that permits to obtain three sheared versions of the microscopic plenoptic map. Digital processing algorithm applied to the maps provides images with resol…
Liquid crystal lens array for 3D microscopy and endoscope application
2016
In this paper, we demonstrate two liquid crystal (LC) lens array devices for 3D microscope and 3D endoscope applications respectively. Compared with the previous 3D biomedical system, the proposed LC lens arrays are not only switchable between 2D and 3D modes, but also are able to adjust focus in both modes. The multi-function liquid crystal lens (MFLC-lens) array with dual layer electrode has diameter 1.42 mm, which is much smaller than the conventional 3D endoscope with double fixed lenses. The hexagonal liquid crystal micro-lens array (HLC-MLA) instead of fixed micro-lens array in 3D light field microscope can extend the effective depth of field from 60 um to 780 um. To achieve the LC le…
Single-shot, dual-mode, water-immersion microscopy platform for biological applications
2018
A single-shot water-immersion digital holographic microscope combined with broadband (white light) illumination mode is presented. This double imaging platform allows conventional incoherent visualization with phase holographic imaging of inspected samples. The holographic architecture is implemented at the image space (that is, after passing the microscope lens), thus reducing the sensitivity of the system to vibrations and/or thermal changes in comparison to regular interferometers. Because of the off-axis holographic recording principle, quantitative phase images of live biosamples can be recorded in a single camera snapshot at full-field geometry without any moving parts. And, the use o…
One-dimensional wavelength multiplexed microscope without objective lens
2009
A new approach aimed to achieve microscopic imaging without objective lenses and based on wavelength multiplexing of the spatial object information is presented. The proposed method is used to develop, construct and experimentally validate a new type of optical microscope having no objective lens and no numerical reconstruction algorithms to allow imaging process. In order to extract the collected spatial information we use a spectrometer as part of our microscope system. Preliminary results are presented while considering two different types of one-dimensional (1-D) objects.