Novel approach for exceeding the resolving power of optical systems

Author(s):  
Zeev Zalevsky ◽  
David Mendlovic ◽  
Adolf W. Lohmann ◽  
Gal Shabtay
2021 ◽  
Vol 11 (5) ◽  
pp. 2081
Author(s):  
Francisco-Javier Moreno-Muro ◽  
Miquel Garrich ◽  
Ignacio Iglesias-Castreño ◽  
Safaa Zahir ◽  
Pablo Pavón-Mariño

Telecom operators’ infrastructure is undergoing high pressure to keep the pace with the traffic demand generated by the societal need of remote communications, bandwidth-hungry applications, and the fulfilment of 5G requirements. Software-defined networking (SDN) entered in scene decoupling the data-plane forwarding actions from the control-plane decisions, hence boosting network programmability and innovation. Optical networks are also capitalizing on SDN benefits jointly with a disaggregation trend that holds the promise of overcoming traditional vendor-locked island limitations. In this work, we present our framework for disaggregated optical networks that leverages on SDN and container-based management for a realistic emulation of deployment scenarios. Our proposal relies on Kubernetes for the containers’ control and management, while employing the NETCONF protocol for the interaction with the light-weight software entities, i.e., agents, which govern the emulated optical devices. Remarkably, our agents’ structure relies on components that offer high versatility for accommodating the wide variety of components and systems in the optical domain. We showcase our proposal with the emulation of an 18-node European topology employing Cassini-compliant optical models, i.e., a state-of-the-art optical transponder proposed in the Telecom Infrastructure Project. The combination of our versatile framework based on containerized entities, the automatic creation of agents and the optical-layer characteristics represents a novel approach suitable for operationally complex carrier-grade transport infrastructure with SDN-based disaggregated optical systems.


1946 ◽  
Vol 24a (4) ◽  
pp. 15-40 ◽  
Author(s):  
L. E. Howlett

The nature of photographic resolving power is discussed and attention called to the widespread misconception of it that exists at the present time. Most of the detailed discussion applies specifically to photographic objectives intended for use in aerial photography but the general approach to their photographic resolving power is applicable to studies of the photographic performance of all types of optical systems. An annulus type of target is proposed as more suitable than line targets. A method is given for the selection of the photographic focal plane when the essential requirement of the photographic use is the acquisition of maximum information. General remarks are made on the proper trend to be followed in the future design of photographic objectives. Results are presented on a study of a number of well known types of photographic objectives used for aerial photography.


2000 ◽  
pp. 271-341 ◽  
Author(s):  
Zeev Zalevsky ◽  
David Mendlovic ◽  
Adolf W. Lohmann

1977 ◽  
Vol 7 (7) ◽  
pp. 918-919
Author(s):  
Aleksei N Malov ◽  
V N Morozov ◽  
I N Kompanets ◽  
Yurii M Popov

2019 ◽  
Author(s):  
Hugo Gruson ◽  
Marianne Elias ◽  
Christine Andraud ◽  
Chakib Djediat ◽  
Serge Berthier ◽  
...  

AbstractIridescent colours are colours that change depending on the angle of illumination or observation. They are produced when light is reflected by multilayer structures or diffracted by gratings. While this phenomenon is well understood for simple optical systems, it remains unclear how complex biological structures interact with light to produce iridescence. There are very few comparative studies at interspecific level (often focusing on a single colour patch for each species), resulting in an underestimation of structure diversity. Using an interdisciplinary approach combining physics and biology, we here quantify the colour and structure of 36 hummingbirds species evenly distributed across the phylogeny. We explore at least 2 patches per species, which are assumed to be under different selective regimes. For each patch, we measure structural features (number of layers, layer width, irregularity, spacing, etc.) of the feathers at different scales using both optical and electronic microscopy and we measure colour using a novel approach we developed to encompass the full complexity of iridescence, including its angular dependency. We discover an unsuspected diversity of structures producing iridescence in hummingbirds. We also study the effect of several structural features on the colour of the resulting signal, using both an empirical and modelling approach. Our findings demonstrate the need to take into account multiple patches per species and suggest possible evolutionary pressures causing the evolutionary transitions from one melanosome type to another.


An investigation is made of the structure of the electromagnetic field near the focus of an aplanatic system which images a point source. First the case of a linearly polarized incident field is examined and expressions are derived for the electric and magnetic vectors in the image space. Some general consequences of the formulae are then discussed. In particular the symmetry properties of the field with respect to the focal plane are noted and the state of polarization of the image region is investigated. The distribution of the time-averaged electric and magnetic energy densities and of the energy flow (Poynting vector) in the focal plane is studied in detail, and the results are illustrated by diagrams and in a tabulated form based on data obtained by extensive calculations on an electronic computor. The case of an unpolarized field is also investigated. The solution is riot restricted to systems of low aperture, and the computational results cover, in fact, selected values of the angular semi-aperture a on the image side, in the whole range 0 ≤ α ≤ 90°. The limiting case α → 0 is examined in detail and it is shown that the field is then completely characterized by a single, generally complex, scalar function, which turns out to be identical with that of the classical scalar theory of Airy, Lommel and Struve. The results have an immediate bearing on the resolving power of image forming systems; they also help our understanding of the significance of the scalar diffraction theory, which is customarily employed, without a proper justification, in the analysis of images in lowaperture systems.


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