Stray light computations: Has nothing changed since the 1970s?

Greynolds, Alan W.

doi:10.1117/12.730258

Cited by 5 publications

(5 citation statements)

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“…An FFT of this size for double-complex 3-component vector data consumes 12GB of memory. This calculation was done using the in-house GelOE software [11] on a 4-year old 2.5Ghz quad-core * |e| e e = ⋅…”

Section: Discussionmentioning

confidence: 99%

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Free-space propagation of extreme NA polarized beams using the vector plane wave spectrum method and multi-gigabyte FFTsV

Greynolds

2009

Optical Modeling and Performance Predictions IV

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Certain lasers can have initial waists only a wavelength or less in size. Therefore, collection optics with extreme numerical apertures (NA) approaching unity are required. Although the design of these macro-optics using geometrical ray-tracing is trivial, determining the exact vectorial field entering them is not. The theory and implementation of Fourier, or plane wave spectrum (PWS), based methods is presented for not only the far-field, but also the near and intermediate. A real-world example is given for which at one point a 12 gigabyte two-dimensional fast Fourier transform (FFT) is required and unexpected polarization effects are observed.

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Section: Discussionmentioning

confidence: 99%

“…and (11), one finds that the far-field from the spectrum of sinc(2r) is a uniform hemi-spherical wave…”

Section: Limiting Formsmentioning

confidence: 98%

Free-space propagation of extreme NA polarized beams using the vector plane wave spectrum method and multi-gigabyte FFTsV

Greynolds

2009

Optical Modeling and Performance Predictions IV

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“…Importance sampling is a technique employed in Monte Carlo calculations to improve efficiency (Greynolds 2007). The "important" surfaces are forced to occur with higher probability than their nature.…”

Section: Importance Samplingmentioning

confidence: 99%

Stray light analysis of the Xinglong 2.16-m telescope

Taoran

Wang

Zhang

et al. 2020

Res. Astron. Astrophys.

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An effort towards understanding of the stray light problems for the Xinglong 2.16-m telescope was presented to estimate the stray light performance of the telescope itself and provide a method for improving the stray light suppression. The stray light analysis for 2.16-m telescope model, which consists the onion shaped dome, telescope structure, equatorial mount and telescope optics, has been performed with two cases (1) point to 60° and (2) point to zenith, in both azimuth and elevation. A simplified mechanical model obtained from the detailed telescope system geometry was used to increase the simulation efficiency. The source setting, property assumptions and ray tracing methodology for stray light simulation are described. The critical and illuminated objects were identified to understand the stray light propagation path in system. The Point source normalized irradiance transmittance (PSNIT), which is generally used for assessing stray light and uncorrelated to entrance aperture was calculated utilizing the stray light software TracePro to evaluate the stray light performance of the 2.16-m telescope with a series of off-axis angles. It shows that the PSNIT values are less than 10 -7 when off-axis angles are larger than ±20°. The dominant objects for stray light (primary and secondary mirror, telescope structure and dome) were identified to give advice for performance improvement. The analyses indicate that significant benefit can be realized with adding only 5 vanes inside the bottom portion of the secondary baffle. In the case of point to zenith, the PSNIT values will decrease about 40% at average.

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“…The mathematical modeling of the effects of flare has a long history, but in the early 1970's, computer software replaced the age-old "build and measure" method of calculating flare 6 . Software can now be used to accurately model the effects of flare, and identify which surfaces in the system are the worst flare contributors.…”

Section: Calculating the Causes And Effects Of Flarementioning

confidence: 99%

“…One ray strikes the surface, and two rays leave: one in the transmitted direction and one in the reflected direction. Next, the maximum number of times a ray can strike the same surface was increased to 1x10 6 . This change allows a ray to propagate even if it gets trapped inside a lens due to TIR conditions, striking the same surface many times.…”

Section: Setup the Modelmentioning

confidence: 99%

Efficient design process for the evaluation and control of flare in opto-mechanical systems

2009

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Even the best optical designs can be ruined by unwanted light: flare in the form of ghost images and veiling glare. The analysis of stray light in an opto-mechanical system is a step in the design process that is often limited to ghost image analysis by the optical designer. In many large design groups, stray light analysis is traditionally performed by optical engineers with very specialized analysis tools that are difficult to master. However, recent improvements in software packages are now offering tools that allow less experienced designers access to tool sets that can perform flare and veiling glare analysis for a substantial subset of optical design problems. This paper outlines an effective and efficient design process for determining the types and magnitudes of stray light in an optical system and demonstrates its use on an injection molded plastic lens assembly. We describe a capability that locates all of the optical paths and their relative magnitudes through an optical system and separates them into one of three categories: image path, ghost paths, or veiling glare. We then describe how to leverage this information to determine the most effective removal method for the "worst offenders".

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Stray light computations: Has nothing changed since the 1970s?

Cited by 5 publications

References 0 publications

Free-space propagation of extreme NA polarized beams using the vector plane wave spectrum method and multi-gigabyte FFTsV

Free-space propagation of extreme NA polarized beams using the vector plane wave spectrum method and multi-gigabyte FFTsV

Stray light analysis of the Xinglong 2.16-m telescope

Efficient design process for the evaluation and control of flare in opto-mechanical systems

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