Kleemann B.H.,Carl Zeiss GmbH
Optics Letters | Year: 2012
Perfect blazing with echelle gratings in a high-order Littrow mount exists not only with TM polarization, as can perhaps be assumed, but also with TE and TM polarizations simultaneously. This finding contradicts with a heuristic explanation as to why perfect blazing is not possible simultaneously in TE and TM polarizations given by Loewen and Popov [Diffraction Gratings and Applications (Marcel Dekker, 1997)]. As a matter of fact, in the ideal case of infinite conductivity, light is diffracted in the Littrow order with 100% efficiency for both polarization states. For metal gratings, a small loss occurs. Three conditions are necessary for perfect blazing: (A) the apex angle must be very close to 90°, (B) a specific Littrow order has to be used, and (C) the blaze angle has to be 4° to 6° larger than the Littrow angle. The last property is particularly intriguing because typically the difference between the two angles is smaller than 1.0°. © 2012 Optical Society of America.
Agency: Cordis | Branch: H2020 | Program: MSCA-ITN-ETN | Phase: MSCA-ITN-2015-ETN | Award Amount: 3.54M | Year: 2016
The proposed ETN Myopia: fundamental understanding needed (MyFUN) provides an international, interdisciplinary platform to train young scientists at the interface of physics and biology, to study unresolved questions about the visual control of eye growth. It has been extensively documented that the growth of the eye is controlled by closed-loop visual feedback, using retinal image defocus as an error signal. However, with tense education, predominant indoor activity and extensive near work, the eyes of young people grow too long and become near-sighted (myopic), reaching a prevalence of 95% in some Asian cities and 50% at German universities. While myopia is clearly a civilization disorder, it is strikingly unclear by which visual stimuli it is triggered, and how it can be stopped. Emerging optical interventions have still only moderate effects. There are fundamental questions, like Why does myopia not limit itself?, Why does undercorrection not reduce its progression?, Why are the effects of new spectacle designs to inhibit myopia so small?, What determines when it starts and can we find biological markers to predict myopia in individual cases?. We propose a scheme of novel experiments, divided into 14 research projects that all have sufficient scientific depth and merit to merge into 14 successful PhD theses. The answers to the research questions will fundamentally improve our understanding of myopia, will be recognized worldwide and will represent a major contribution of the European Community to the global problem of the rising incidence of myopia. Our consortium consists of 7 Beneficiaries, combining the expertise of 5 academic partners with excellent research and teaching records and 2 fully integrated private sector partners. MyFUN will be supported by a management team experienced in multi-site training activities and counselled by a scientifically accomplished External Advisory Board.
Carl Zeiss GmbH | Date: 2015-10-29
The invention is directed to a system for determining the refractive properties of an eye. The system includes a wavefront measurement device for measuring the refractive properties of the eye. The system is configured to have at least one measurement mode assigned to children, wherein the system has an input device configured to switch the system into one of the at least one measurement mode assigned to children. The system is further configured to alter at least one of a group including a default pupillary distance, a default cornea vertex distance, a default position of the wavefront measurement device, a default position and/or direction of a measurement ray of the wavefront measurement device, a default position of a forehead and chin rest assembly of the system and a fixation target when the system is switched into the one of the at least one measurement mode assigned to children.
Carl Zeiss GmbH | Date: 2015-01-15
Systems and methods for expanding the field-of-view of ophthalmic scanning devices are presented. An ophthalmic scanning device is designed such that the pivot point of the scanning optics is maintained at a fixed location in the pupil while the scanning optics are rotated about the eye to obtain imaging data over an increased field-of-view than can be achieved by the scanning optics alone. The rotation can be achieved using a singular rotational motion of the scanning optics about a rotational axes coincident with the scanning pivot point or can be achieved using a combination of rotational motion with a second motion either rotational or translational to maintain the scanning pivot point at the fixed location. Embodiments related to optical coherence tomography and scanning laser ophthalmoscopy are described.
Carl Zeiss GmbH | Date: 2016-01-11
An optical hollow waveguide assembly (