Search results for "achromatic"
showing 10 items of 49 documents
Broadband focused waves with compensated spatial dispersion: transverse versus axial balance.
2007
We determine the constraints an ABCD optical system must verify to achieve, at the focal region, broadband waves with compensated spatial dispersion either along the optical axis, called on-axis isodiffracting fields, or in the lateral direction, here named in-plane isodiffracting beams. An optical configuration is identified for generating both types of achromatic broadband focused wave fields. An experimental verification is also provided.
Single-zone-plate achromatic fresnel-transform setup: Pattern tunability
1997
Abstract White-light point-source illumination results in the chromatic blurring of the optical field diffracted by an aperture. In this paper, broadband dispersion compensation for a continuous set of Fresnel diffraction patterns associated with an arbitrary input transparency is carried out, in a sequential way, by means of a single on-axis blazed zone plate. The input is illuminated with a white-light converging spherical wavefront and the diffractive lens is inserted at the virtual source plane. We recognize that the position of the input along the optical axis permits to achieve a different achromatic Fresnel diffraction pattern with low residual chromatic aberrations. The theory deriv…
Totally incoherent optical processing operations with achromatic diffraction-based setups
2000
We report on a novel family of totally incoherent, chromatic-dispersion compensated hybrid (refractive-diffractive) lens setups for implementing, in the Fraunhofer or in the Fresnel diffraction region, different achromatic diffraction-based processing operations.
High-contrast white-light Lau fringes
2004
We present a new optical assembly with which to achieve Lau fringes with totally incoherent illumination. Gratinglike codification of the spatially incoherent source combined with an achromatic Fresnel diffraction setup allows us to achieve Lau fringe-pattern visibility of almost 100% with broadband light. The white-light character to our proposed setup is in stark contrast to previous monochromatic implementations. Potential implications of this fact are identified.
Chromatic-achromatic perimetry in four clinic cases: Glaucoma and diabetes
2015
Color perimetry has interesting clinical application for the diagnosis and detection of certain eye conditions, due to the variations that certain diseases can cause in chromatic thresholds, both in the red-green (RG) and the blue-yellow (BY) pathways.[1,2,3,4] The separate study of the visual function of both the chromatic and achromatic mechanisms could be more efficient in detecting sensitivity variations, and such variations would not be obscured by the intrusion of other mechanisms. Currently, the supply of conventional perimeters that are capable of performing a chromatic perimetry test is very limited and with reduced options regarding the possibility of choosing the physical charact…
Retinopathia Pigmentosa Plus - the Value of Ultra-Structural Examination of the Human Retina
1993
Retinopathia pigmentosa is more widely, but somewhat incorrectly known as Retinitis pigmentosa (RP). Its course as a primary exclusively retinal disease follows autosomal-dominant, autosomal-recessive, or X-linked recessive modes of inheritance, or it may be sporadic. However, a progressive retinopathy, also called tapeto-retinal degeneration, may also be associated with numerous disorders: retinopathia pigmentosa plus (RPP). Among these RPP are those which form part of certain syndromes, e.g. Laurence-Moon-Bardet-Biedl syndrome, the Hallgren syndrome, the Marinesco-Sjogren syndrome, to name a few. Other RPP are associated with disorders of different organs, the skin, e.g. Werner disease, t…
Achromatic Varifocal Metalens for the Visible Spectrum
2019
Metasurface optics provide an ultra-thin alternative to conventional refractive lenses. A present challenge is in realizing metasurfaces that exhibit tunable optical properties and achromatic behavior across the visible spectrum. Here, we report the design, fabrication, and characterization of metasurface lenses ("metalenses") that use asymmetric TiO2 nanostructures to induce a polarization-dependent optical response. By rotating the polarization of linearly-polarized input light, the focal length of a 40 micrometer-diameter metalens is tuned from 220-550 micrometers with nearly diffraction-limited performance. We show that imparting a wavelength-dependent polarization rotation on incident …
Preliminary clinical efficacy and safety of BMN 701, GILT-tagged recombinant human acid alpha glucosidase (rhGAA), in late-onset Pompe disease: resul…
2014
Metachromatic leukodystrophy (MLD) is a lysosomal disorder that results from the deficiency of the lysosomal enzyme arylsulfatase A. It is characterized by motor and developmental regression, seizures, deafness, blindness, dementia and premature death. There are three types of onsets: late infantile, juvenile, and adult. We performed a retrospective chart review of 71 patients (47 infantile, 23 juvenile) evaluated at the Program for Study of Neurodevelopment in Rare Disorders (NDRD) between January 2000 and August 2013. The patients were evaluated prospectively using a standardized protocol. The purpose of the study is to describe the natural course of the disease. In 31 patients only a bas…
Experimental program of the Super-FRS Collaboration at FAIR and developments of related instrumentation
2016
The physics program at the super-conducting fragment separator (Super-FRS) at FAIR, being operated in a multiple-stage, high-resolution spectrometer mode, is discussed. The Super-FRS will produce, separate and transport radioactive beams at high energies up to 1.5 AGeV, and it can be also used as a stand-alone experimental device together with ancillary detectors. Various combinations of the magnetic sections of the Super-FRS can be operated in dispersive, achromatic or dispersion-matched spectrometer ion-optical modes, which allow measurements of momentum distributions of secondary-reaction products with high resolution and precision. A number of unique experiments in atomic, nuclear and h…
Clinical and histological diagnosis of a case of familial adult metachromatic leucodystrophy
1974
Die detaillierte nosographische Analyse eines 25jahrigen Patienten mit adulter metachromatischer Leukodystrophie wird mitgeteilt. Der Patient zeigt langsam progrediente psychische, charakterliche, intellektuelle, zentralund periphernervose Veranderungen. — Die biochemische Diagnostik ergab einen weitgehenden Arylsulfatase A-Mangel in Urin und Leukocyten sowie eine erhohte Sulfatidausscheidung im Urin (2–7 mg je Liter). — Durch histochemische Untersuchungen einer Nervus suralis-Biopsie wurde metachromatisches Speichermaterial nachgewiesen.