Searched for: subject%3A%22Design%22
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Hou, Z. (author), Bociort, F. (author)
A major challenge in lens design is the presence of many local minima in the optimization landscape. However, unlike other global optimization problems, the lens design landscape has an additional structure, that can facilitate the design process: many local minima are closely related to minima of simpler problems. For discussing this property,...
conference paper 2015
document
Bociort, F. (author), van Grol, P. (author)
Understanding the structure of the design space in optical system optimization is difficult, because common human intuition fails when it encounters the challenge of high dimensionality, resulting from the many optimization parameters of lens systems. However, a deep mathematical idea, that critical points structure the properties of the space...
conference paper 2012
document
Bociort, F. (author), Van Grol, P. (author)
In this paper we describe new properties of the design landscape that could lead in the future to a new way to determine good starting points for subsequent local optimization. While in optimization the focus is usually only on local minima, here we show that points selected in the vicinity of other types of critical points (i.e. points where...
conference paper 2010
document
Bociort, F. (author)
The presence of many local minima in the merit function landscape is perhaps the most difficult challenge in lens design. We present a simplified mathematical model that illustrates why the number of local minima increases rapidly with each additional lens added to the imaging system. Comparisons with results obtained with lens design software...
conference paper 2010
document
Bociort, F. (author), Van Grol, P. (author)
In this paper we describe new properties of the design landscape that could lead in the future to a new way to determine good starting points for subsequent local optimization. While in optimization the focus is usually only on local minima, here we show that points selected in the vicinity of other types of critical points (i.e. points where...
conference paper 2010
document
Van Grol, P. (author), Bociort, F. (author), Van Turnhout, M. (author)
Contrary to the frequent tacit assumption that the local minima of a merit function are points scattered more or less randomly over the design landscape, we have found that, at least for simple imaging systems (doublets with three and triplets with five variables) all design shapes we have observed thus far form a strictly ordered set of points,...
conference paper 2009
document
Bociort, F. (author), Van Turnhout, M. (author)
journal article 2009
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Van Turnhout, M. (author), Bociort, F. (author)
In lens design, damped least-squares methods are typically used to find the nearest local minimum to a starting configuration in the merit function landscape. In this paper, we explore the use of such a method for a purpose that goes beyond local optimization. The merit function barrier, which separates an unsatisfactory solution from a...
journal article 2009
document
Van Turnhout, M. (author), Bociort, F. (author)
Many optical design programs use various forms of the damped least-squares method for local optimization. In this paper, we show that damped least-squares algorithms, with maximized computational speed, can create sensitivity with respect to changes in initial conditions. In such cases, starting points, which are very close to each other, lead...
journal article 2009
document
Marinescu, O. (author), Bociort, F. (author)
journal article 2008
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Marinescu, O. (author), Bociort, F. (author)
journal article 2008
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Marinescu, O. (author), Bociort, F. (author)
The merit function space of mirror system for extreme ultraviolet (EUV) lithography is studied. Local minima situated in the multidimensional optical merit function space are connected via links that contain saddle points and form a network. We present networks for EUV lithographic objective designs and discuss how these networks change when...
journal article 2007
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Van Turnhout, M. (author), Bociort, F. (author)
Local optimization algorithms, when they are optimized only for speed, have in certain situations an unpredictable behavior: starting points very close to each other lead after optimization to different minima. In these cases, the sets of points, which, when chosen as starting points for local optimization, lead to the same minimum (the so...
conference paper 2007
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Bociort, F. (author), Van Turnhout, M. (author), Marinescu, O. (author)
Saddle-point construction (SPC) is a new method to insert lenses into an existing design. With SPC, by inserting and extracting lenses new system shapes can be obtained very rapidly, and we believe that, if added to the optical designer’s arsenal, this new tool can significantly increase design productivity in certain situations. Despite the...
conference paper 2007
document
Bociort, F. (author), Van Turnhout, M. (author)
In present-day optical system design, it is tacitly assumed that local minima are points in the merit function landscapewithout relationships between them. We will show however that there is a certain degree of order in the design landscapeand that this order is best observed when we change the dimensionality of the optimization problem and when...
conference paper 2006
document
Marinescu, O. (author), Bociort, F. (author)
Optical designers often insert or split lenses in existing designs. Here, we present, with examples from Deep and Extreme UV lithography, an alternative method that consists of constructing saddle points and obtaining new local minima from them. The method is remarkable simple and can therefore be easily integrated with the traditional design...
conference paper 2006
document
Marinescu, O. (author), Bociort, F. (author)
The multidimensional merit function space of complex optical systems contains a large number of local minima that are connected via links that contain saddle points. In this work, we illustrate a method to construct such saddle points with examples of deep UV objectives and extreme UV mirror systems for lithography. The central idea of our...
conference paper 2005
document
Bociort, F. (author), Van Turnhout, M. (author)
Finding multiple local minima in the merit function landscape of optical system optimization is a difficult task, especially for complex designs that have a large number of variables. We discuss here a method that enables a rapid generation of new local minima for optical systems of arbitrary complexity. We have recently shown that saddle points...
conference paper 2005
document
Marinescu, O. (author), Bociort, F. (author)
The merit function space of mirror systems for EUV lithography is studied. Local minima situated in a multidimensional merit function space are connected via links that contain saddle points and form a network. In this work we present the first networks for EUV lithographic objectives and discuss how these networks change when control parameters...
conference paper 2005
document
Serebriakov, A. (author), Bociort, F. (author), Braat, J. (author)
In the year 2001 it was reported that the birefringence induced by spatial dispersion (BISD), sometimes also called intrinsic birefringence, had been measured and calculated for fluorides CaF2 and BaF2 in the deep UV range. It was also shown that the magnitude of the BISD in these cubic crystals is sufficiently large to cause serious problems...
conference paper 2005
Searched for: subject%3A%22Design%22
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