Improvement of resolving power of optical systems by a new optical element

1954 ◽  
Vol 3 (1) ◽  
pp. 147-148
Author(s):  
A. Bouwers
1999 ◽  
Author(s):  
Zeev Zalevsky ◽  
David Mendlovic ◽  
Adolf W. Lohmann ◽  
Gal Shabtay

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.


Author(s):  
Jennifer Batson ◽  
Ab Hashemi

In modeling space optical systems, an important property affecting the wave front error is the coefficient of thermal expansion (CTE) of the materials. The change of deformation that an optical element experiences due to thermal loads is proportional to both the CTE and the change in temperature gradient. This deformation affects the performance of the optical system by introducing error in the wave front. The deformation can be reduced in part by using materials with low CTE. Alternatively, using high conductivity materials to minimize temperature gradients through the mirror can also reduce deformation. Usually, a combination of these approaches is used to optimize the performance and meet the requirements of the system. Even with the utmost attention to thermal control, often the temperature gradients cannot be completely avoided. Low CTE materials have been developed to reduce thermal deformation, including ULE (Ultra-low Expansion), Zerodur, and Silicon Carbide. However, the manufacturing process can result in non-uniformities throughout the optics. For optical systems requiring highly precise performance, modeling these non-uniformities becomes important. The non-uniformity in the CTE of a material in effect compounds the deformation in the same manner as introducing additional temperature gradient through the optics. This paper describes the methodology for integrated thermal/mechanical modeling to predict the deformation response of an optical element with assumed CTE variations and thermal disturbances. A mirror with an assumed CTE variation was modeled in a changing thermal environment and using IDEAS/TMG analysis tools, thermal deformations were predicted. Results show excellent agreement with engineering predictions. Clearly knowing the CTE variation of the material is a critical step for modeling. However, measuring and specifying the material CTE is out of the scope of this paper.


2012 ◽  
Vol 571 ◽  
pp. 175-179
Author(s):  
Ke Feng ◽  
Jin Song Li ◽  
Ling Guo

Flat-top focus shaping using effect of polarization is investigated theoretically by vector diffraction theory. We demonstrate how to make a properly selected polarization component to achieve a flat-top focus in high numerical apertures optical systems, hence achieving a potential goal of beam shaping. The results show that the values of the polarization angle corresponding to different numerical apertures (NA)values for a flat-top focus and the polarization angle increases on increasing NA for achieving a flat-top focal spot, but the flat-top focal pattern will become -sensitive when NA is larger than 1. One will have to add a diffractive optical element to achieve a flat-top focal spot in NA larger than 1 system.


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

2012 ◽  
Vol 217-219 ◽  
pp. 1646-1649 ◽  
Author(s):  
Chia Jung Chang ◽  
Choung Lii Chao ◽  
Wen Chen Chou ◽  
Yu Kun Chen ◽  
Kung Jeng Ma ◽  
...  

Driven by the huge market demand, the glass lenses made of various optical glasses are required to be more diversified in sizes/shapes, to have better form accuracy/ surface roughness, to be more environmental durable, and to be more competitive in price. In comparison to conventional refractive lens, diffractive lens (diffractive optical element, DOE) has the advantages of being thinner and lighter, and is widely used in optical systems such as lighting and photovoltaic systems. Glass moulding process(GMP) is regarded as a very promising technique for mass producing high precision optical components such as spherical/ aspheric glass lenses and free-form optics. However, only a handful of materials can sustain the chemical reaction, mechanical stress and temperature involved in the glass moulding process. Besides, almost all of these mould materials are classified as hard-to-machine materials. This makes the machining of these materials to sub-micrometer form accuracy and nanometer surface finish a rather tough and expensive task. As a result, making service life of mould longer has played a critical part in the GMP industry. The excessive stress and/or temperature involved in the moulding process are amongst the main reasons for pre-matured mould failure. This research aimed to analyze the stress/strain conditions and the obtained dimensional accuracy under various molding parameters by simulations. Molding experiments were subsequently carried out to verify the simulated results. A glass DOE of 14.8 mm in diameter and 3.36 mm in thickness are successfully produced in this research and the difference between the simulated and the molded DOE is around 15μm.


2020 ◽  
Vol 10 (20) ◽  
pp. 7210
Author(s):  
Jürgen Probst ◽  
Christoph Braig ◽  
Alexei Erko

We report on the first experimental results obtained with a newly designed instrument for high-resolution soft X-ray spectroscopy, using reflection zone plates (RZPs) on a spherical substrate. The spectrometer was tested with a fluorescence source. High-resolution flat field spectra within ±50% around the design energies were measured at an interval of 150–750 eV, using only two RZPs: the first RZP, with its design energy of 277 eV, covered the band of 150–370 eV, and the second RZP, with a design energy of 459 eV, covered the band of 350–750 eV, where the upper boundary of this energy range was defined by the Ni coating of the RZPs. The absolute quantum efficiency of the spectrometer, including the optical element and the detector, was, on average, above 10%, and reached 20% at the designed energies of the RZPs. The resolving power E/∆E exceeded 600 for energies E inside the core range of 200–550 eV.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2455 ◽  
Author(s):  
Juan Ferrer-Rodríguez ◽  
Alvaro Valera ◽  
Eduardo Fernández ◽  
Florencia Almonacid ◽  
Pedro Pérez-Higueras

The recent development of wafer bonded four-junction concentrator solar cells (FJSCs) with record efficiency among all the existent photovoltaic (PV) cells offers new possibilities for improving the High Concentrator PV (HCPV) technology. However, the concentrator optical systems utilized in HCPV modules may have to be adapted to the new requirements of FJSC in order to properly take advantage of the increased number of p-n junctions. This research theoretically compares two identical optical concentrator systems, a Frensel lens plus a kind of refractive SILO (SIngle-Lens-Optical element) secondary (both made of PMMA, poly(methyl methacrylate)), which are equipped with a typical triple-junction concentrator solar cell (TJSC) in the one case, and with an FJSC in the other case. Both HCPV units are analyzed through ray tracing optical simulations applying an exhaustive optical modelling that takes into account the spectral responses of the different subcells within the multi-junction cells. The HCPV unit with the FJSC and PMMA SOE (secondary optical element) shows much less efficiency than that with the TJSC due to the light absorption through the PMMA SOE in the wavelength range of the bottom subcell. Therefore, PMMA SOEs may be not appropriate for FJSC in general.


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

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