The Experts below are selected from a list of 1083 Experts worldwide ranked by ideXlab platform
Moore, Duncan T. - One of the best experts on this subject based on the ideXlab platform.
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Design of axial gradient singlets utilizing a Fickian diffusion model
'University of Rochester Press', 2017Co-Authors: Hoppe, Michael James, Moore, Duncan T., Douglas Scott - ) KindredAbstract:Thesis (M.S.)--University of Rochester. College of Engineering and Applied Science. Institute of Optics.The manufacture of a Lens system containing a gradient index (GRIN) Lens or Lenses is a difficult process. The root of this difficulty is the gap in communication between the Lens Designer and the GRIN manufacturer. Typically the GRIN profile is described using coefficients of a polynomial expansion of the index of refraction. However, these abstract quantities give no insight or intuition as to how to manufacture the profile. In trying to bridge the gap between Designer and manufacturer, this thesis poses a new way for the Lens Designer to express the profile in terms that are consistent with that of a GRIN manufacturer. One way to manufacture GRIN is by a diffusion process, ion exchange. By allowing the computer to solve and optimize on a mathematical representation of diffusion, the resultant profile, and more importantly, the resultant design will more closely depict the final production Lens. A method to solve the diffusion equation and link it to a common Lens design program, Code V™ is offered. Several Lenses containing theoretical axial gradients are optimized and their performances were evaluated. In addition, an empirical diffusion model is developed based on a known glass system and a singlet is optimized containing an axial gradient calculated using this diffusion model
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Integration of the design and manufacture of gradient-index optical systems
'University of Rochester Press', 2017Co-Authors: Bentley, Julie L., Moore, Duncan T.Abstract:Thesis (Ph. D.)--University of Rochester. Institute of Optics, 1995.Modern manufacturing incorporates fabrication constraints and quality control into the initial product design to create competitive, cost-effective products. This research offers a design-for-manufacture approach to gradient-index Lens production. Fabrication parameters are coupled to a Lens design program to eliminate the traditional trial-and-error manufacturing process. The new approach allows a Lens Designer to design a gradient-index optical system in terms of the actual fabrication parameters and then provides a set of experimental specifications to the materials scientist. The result is a more efficient and cost-effective manufacturing process for gradient-index optical systems. Traditional gradient-index design methods were developed before many of the current gradient-index materials were available and are therefore unrelated to the material fabrication parameters. For example, the index of refraction profile is typically expressed by a polynomial expansion in optical design. Once a Lens is designed with this representation, the manufacturer must guess at fabrication parameters such as time and temperature to obtain the required 4 depth, and profile shape. As a result the design-to-manufacture process is slow and iterative. Therefore, a more efficient design-for-manufacture approach is offered by this research. First, a mathematical model for gradient-index fabrication by ion exchange is developed using Fickian diffusion theory. Second, an experimental procedure is developed to test this model against experimental results for several different diffusion times and temperatures in both axial and radial sample geometries. In particular, empirical diffusion models are developed for Li+ for Na+ and Na+ for Li+ ion exchange in alumina silicate glasses, alumina borate glasses, and titania silicate glasses. Third, the model is integrated with a Lens design program to allow optimization on diffusion parameters and several sample designs are presented which compare the old design procedure with this new method of design. Thus, with the completion of this research, a Lens Designer can now choose from a realistic set of gradient index glasses and, in turn, generate a complete set of experimental specifications for the production of the gradient
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Development of new gradient index glasses for optical imaging systems
University of Rochester, 2017Co-Authors: Douglas Scott - ) Kindred, Moore, Duncan T.Abstract:Thesis (Ph. D.)--University of Rochester. College of Engineering and Applied Science. Institute of Optics, 1990.Previous research has shown that many imaging systems can benefit from the use of gradient index (GRIN) materials. The required number of Lens elements can often be reduced or the system performance can be improved. The use of gradient index Lenses has not become widespread, however, largely due to three major problems. The first is that there is a lack of available gradient index materials. Lens Designers require glasses with a wide range of refractive index and dispersions in both homogeneous and gradient index systems. Very few GRIN glasses have been developed and only small diameter ( 1-3 mm) gradient index rods are commercially available, leaving virtually nothing for the Lens Designer. The second problem is that adequate control of the index of refraction profile must be achieved. This is necessary in order to control the aberrations of the systems in question. The last problem is that the mathematical representation of the index of refraction profile is not currently linked to the fabrication parameters, thus making it difficult to manufacture a Lens once it has been designed. This work concentrates largely on the first of these problems. Several new glasses have been developed which are suitable for fabricating both axial and radial gradients by Ag⁺ - Na⁺ and Li⁺ - Na⁺ ion exchange. New crown glasses, flint glasses and high index crowns with both positive and negative index changes are presented. A variety of refractive index profiles with different index changes (An), and dispersive properties are also shown. The ion exchange properties of the glasses were investigated using conventional Fickian diffusion models and the refractive index profiles were modeled using Fantone's adaptation of the Gladstone-Dale equation. The usefulness of these glasses in optical systems is assessed and a procedure for designing Lenses with manufacturable index profiles is also demonstrated
Bentley, Julie L. - One of the best experts on this subject based on the ideXlab platform.
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Integration of the design and manufacture of gradient-index optical systems
'University of Rochester Press', 2017Co-Authors: Bentley, Julie L., Moore, Duncan T.Abstract:Thesis (Ph. D.)--University of Rochester. Institute of Optics, 1995.Modern manufacturing incorporates fabrication constraints and quality control into the initial product design to create competitive, cost-effective products. This research offers a design-for-manufacture approach to gradient-index Lens production. Fabrication parameters are coupled to a Lens design program to eliminate the traditional trial-and-error manufacturing process. The new approach allows a Lens Designer to design a gradient-index optical system in terms of the actual fabrication parameters and then provides a set of experimental specifications to the materials scientist. The result is a more efficient and cost-effective manufacturing process for gradient-index optical systems. Traditional gradient-index design methods were developed before many of the current gradient-index materials were available and are therefore unrelated to the material fabrication parameters. For example, the index of refraction profile is typically expressed by a polynomial expansion in optical design. Once a Lens is designed with this representation, the manufacturer must guess at fabrication parameters such as time and temperature to obtain the required 4 depth, and profile shape. As a result the design-to-manufacture process is slow and iterative. Therefore, a more efficient design-for-manufacture approach is offered by this research. First, a mathematical model for gradient-index fabrication by ion exchange is developed using Fickian diffusion theory. Second, an experimental procedure is developed to test this model against experimental results for several different diffusion times and temperatures in both axial and radial sample geometries. In particular, empirical diffusion models are developed for Li+ for Na+ and Na+ for Li+ ion exchange in alumina silicate glasses, alumina borate glasses, and titania silicate glasses. Third, the model is integrated with a Lens design program to allow optimization on diffusion parameters and several sample designs are presented which compare the old design procedure with this new method of design. Thus, with the completion of this research, a Lens Designer can now choose from a realistic set of gradient index glasses and, in turn, generate a complete set of experimental specifications for the production of the gradient
Douglas Scott - ) Kindred - One of the best experts on this subject based on the ideXlab platform.
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Design of axial gradient singlets utilizing a Fickian diffusion model
'University of Rochester Press', 2017Co-Authors: Hoppe, Michael James, Moore, Duncan T., Douglas Scott - ) KindredAbstract:Thesis (M.S.)--University of Rochester. College of Engineering and Applied Science. Institute of Optics.The manufacture of a Lens system containing a gradient index (GRIN) Lens or Lenses is a difficult process. The root of this difficulty is the gap in communication between the Lens Designer and the GRIN manufacturer. Typically the GRIN profile is described using coefficients of a polynomial expansion of the index of refraction. However, these abstract quantities give no insight or intuition as to how to manufacture the profile. In trying to bridge the gap between Designer and manufacturer, this thesis poses a new way for the Lens Designer to express the profile in terms that are consistent with that of a GRIN manufacturer. One way to manufacture GRIN is by a diffusion process, ion exchange. By allowing the computer to solve and optimize on a mathematical representation of diffusion, the resultant profile, and more importantly, the resultant design will more closely depict the final production Lens. A method to solve the diffusion equation and link it to a common Lens design program, Code V™ is offered. Several Lenses containing theoretical axial gradients are optimized and their performances were evaluated. In addition, an empirical diffusion model is developed based on a known glass system and a singlet is optimized containing an axial gradient calculated using this diffusion model
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Development of new gradient index glasses for optical imaging systems
University of Rochester, 2017Co-Authors: Douglas Scott - ) Kindred, Moore, Duncan T.Abstract:Thesis (Ph. D.)--University of Rochester. College of Engineering and Applied Science. Institute of Optics, 1990.Previous research has shown that many imaging systems can benefit from the use of gradient index (GRIN) materials. The required number of Lens elements can often be reduced or the system performance can be improved. The use of gradient index Lenses has not become widespread, however, largely due to three major problems. The first is that there is a lack of available gradient index materials. Lens Designers require glasses with a wide range of refractive index and dispersions in both homogeneous and gradient index systems. Very few GRIN glasses have been developed and only small diameter ( 1-3 mm) gradient index rods are commercially available, leaving virtually nothing for the Lens Designer. The second problem is that adequate control of the index of refraction profile must be achieved. This is necessary in order to control the aberrations of the systems in question. The last problem is that the mathematical representation of the index of refraction profile is not currently linked to the fabrication parameters, thus making it difficult to manufacture a Lens once it has been designed. This work concentrates largely on the first of these problems. Several new glasses have been developed which are suitable for fabricating both axial and radial gradients by Ag⁺ - Na⁺ and Li⁺ - Na⁺ ion exchange. New crown glasses, flint glasses and high index crowns with both positive and negative index changes are presented. A variety of refractive index profiles with different index changes (An), and dispersive properties are also shown. The ion exchange properties of the glasses were investigated using conventional Fickian diffusion models and the refractive index profiles were modeled using Fantone's adaptation of the Gladstone-Dale equation. The usefulness of these glasses in optical systems is assessed and a procedure for designing Lenses with manufacturable index profiles is also demonstrated
Herbert Gross - One of the best experts on this subject based on the ideXlab platform.
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Zernike surface contributions as an assisting tool for designing freeform optical systems
Optical Design and Engineering VII, 2018Co-Authors: Mateusz Oleszko, Herbert GrossAbstract:The application of freeform elements in optical systems increases the number of design variables. In order to use the additional degrees of freedom most efficiently for correcting the system, the optimization process requires a guidance from the Lens Designer. The knowledge of aberrations generated in the system provides insights for selecting the best starting configuration as well as for choosing the position of the freeform element. In this work we use a new numerical method [Oleszko et al., JOSAA Vol. 34(10), 1856 (2017)] to study surface-by-surface contributions to the total wave aberration of freeform optical systems. Surface contributions are divided due to their origin into intrinsic, induced and transfer components. The study of intrinsic and induced effects assists in finding design solutions corrected for aberrations of orders higher than the fourth in the expansion of the wave aberration function. In contrast to the analytical approach, the method does not incorporate the field dependency into the wave aberrations and the error of the chief ray is studied separately. That allows to visualize the distortion of the image grid at the intermediate image planes.
Joh Franks - One of the best experts on this subject based on the ideXlab platform.
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challenges constraints and results of Lens design in 8 12micron waveband for bolometer fpas having a pixel pitch 12micron
Proceedings of SPIE, 2013Co-Authors: Norbe Schuste, Joh FranksAbstract:In the 8-12 micron waveband Focal Plane Arrays (FPA) are available with a pixel pitch of 12 microns or less. High resolution FPAs with VGA, XGA and SXGA resolution should become available at a reasonable price. These will require new Lens designs to give the required fields of view. The challenge for the Optical Designer is to design Lenses when the pixel pitch of the detector is the same as the wavelength of the light imaged. The Lens specification will need to give more thought to the resolution required by the system. A smaller pixel pitch detector defines a requirement for a shorter focal length to give the same field of view. This will have a number of effects upon the Lens design. Geometrical aberrations decrease proportionally with the focal length. Reverse telephoto layouts will become more common, particularly when the system has a shutter. The increase in pixel count will require wide field of view Lenses which present particular challenges. The impact of diffraction effects on the Lens design is considerably increased. The fast F-number causes an increase in the diffraction limit of the system, but also increases geometric aberrations by a cube law. Therefore the balance between the diffraction limited and the aberration limited performance becomes more difficult. The first approach of the Designer is to re-use proven designs originally intended for use with 17micron detectors. Some of these designs will have adequate performance at the Nyquist limit of the 12 micron detectors. Even smaller detector pitches, such as 10 micron, will demand new approaches to Infra Red Lens design. The traditional approach will quickly increase the number of elements to 3 or even more. This could lead to the Lenses with medium fields of view driving the system cost. A close cooperation between the camera developer and Lens Designer will become necessary in order to explore alternate approaches, such as wavefront coding, in order to reach the most cost effective solution.