Proceedings Volume 4832

International Optical Design Conference 2002

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Proceedings Volume 4832

International Optical Design Conference 2002

View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 23 December 2002
Contents: 13 Sessions, 66 Papers, 0 Presentations
Conference: International Optical Design Conference 2002 2002
Volume Number: 4832

Table of Contents

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Table of Contents

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  • Modeling Optical Surfaces and Systems
  • Head-Mounted Displays
  • Lens Design
  • Lithography Systems
  • Optical Design Theory
  • Large-Telescope Technology
  • Illumination Systems
  • NIF and IR Optical Systems
  • Diffraction and Beam Propagation
  • Conformal Optics, PALs, and Eye Modeling
  • Photonics Systems
  • IODC Problem Session
  • Poster Session
  • Lens Design
Modeling Optical Surfaces and Systems
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Superconic and subconic surface descriptions in optical design
The superconic surface description has been around since 1986 and more recently implemented in commercial design software. A simpler version dubbed the 'subconic' is proposed and appears to work well in applications requiring steep aspherics.
Optical design with rotationally symmetric NURBS
The standard aspheric surface, a conic surface figured with a polynomial expansion, provides excellent correction in many optical design problems. But there are problems where this set of basis functions does not provide the best solution. This paper discusses a parametric curve alternative called Non-Uniform Rational B-Splines (NURBS). NURBS are used extensively in the computer aided geometric design industry (CAGD) because they offer a rational segmented polynomial curve with the flexibility of setting both the order of the B-spline segments and the locations of the knots, or joints, between the B-spline segments providing local curve control. In addition, they are numerically stable and they have geometric intuitive control points for manipulating the curve. The advantages and disadvantages of using NURBS in optical design applications are discussed. Brief explanations of NURBS curve mathematics, properties, and design techniques are presented. The paper concludes with an optical design example comparing the optical performance between rotationally symmetric NURBS surfaces and standard aspheric surface. Note that all of the aspheric surfaces discussed in this paper are rotationally symmetric.
Nonanamorphic imaging with three conic mirrors
Design methods are described for unobstructed, plane-symmetric systems composed of three conic mirrors. Low order imaging constraints (including the requirement of nonanamorphism) are used to reduce the dimensionality of the configuration space. Examples are presented.
Unobscured mirror designs
This paper reviews unobscured multiple-mirror imaging designs ranging from two to many mirrors, the ranges of operating conditions of each configuration, their strengths and limitations, and areas of application.
Head-Mounted Displays
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Wide-field-of-view wide-spectral-band off-axis helmet-mounted display optical design
C. Bill Chen
This paper describes some basic principles associated with the optical design of an ultra-wide field of view, wide spectral band off-axis helmet-mounted display (HMD). To simplify the HMD optics, diffractive optical element and/or plastic lenses are employed. Several design exmaples are given to illustrate the design principles.
Design of a wearable wide-angle projection color display
In this paper, we investigate the design and fabrication of ultra-light weight projection lenses for color wearable displays. Driven by field of view requirements from 40 degree to 90 degrees, we employed the combination of plastic, glass, and diffractive optics to yield less than 10g optics per eye. The approach centers on the use of projection optics instead of eyepiece optics to yield most compact and high image quality designs. The implementation of the fabricated 52 degrees lens in a teleportal head-mounted display and remote collaborative environment is demonstrated. We also present the design results for a 70 degrees design.
Compact relay lenses using microlenslet arrays
In an investigation of approaches to compact relay lenses for special effect photography, the potential of microlenslet arrays in image formation is investigated. In this paper, various arrangements of microlenslet arrays and associated baffles are considered and their role on image quality presented. Findings through software simulations clearly demonstrate the trade-offs between image quality and compactness.
Optical design of a monocentric autostereoscopic immersive display
Joshua M. Cobb, David Kessler, John A. Agostinelli
An optical design of an autostereoscopic immersive video display is described. The apparatus uses pupil imaging with a curved mirror to achieve autostereoscopic performance. It employs a monocentric design to enable a wide field of view and large pupils while keeping the lens diameters small to fit them within the interocular separation.
Lens Design
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Fifty years of lens design: What do we know now that we did not know then?
Robert R. Shannon
This presentation examines the extent to which the knowledge of how lenses function has (or has not) kept pace with the computational ability developed over the past five decades, and how this has influenced progress in the field of optical design.
Index inhomogeneity effects on imaging systems (Summary)
Brian L. Stamper, James H. Burge
Large field of view, high power, lithography, and laser fusion systems are all limited by refractive index variations of their constituent glass elements. To estimate how the image degrades, a model ofthe bulk index inhomogeneity must be fonned.
Zoom lens with "electronic" curves
Eckhard Langenbach, Hans-Joerg Heimbeck, Eckhard List
A zoom lens with two independently driven lens groups is presented. In contrast to conventional zooms each lens has its own individual and temperature dependent zoom curves, which are determined with an interferometric test setup.
Reduced manufacturing sensitivity in multi-element lens systems
Mark Jeffs
Maximizing the as-built system performance is the real task of the lens designer. If a lens is to be built, then tolerance sensitivity is always an issue. A range of techniques for de-sensitization is presented, with illustrative examples from recent design projects.
Novel method for precise focal length measurement
A new technique for precise focal length measurements by use of a hologram is presented. The hologram is used in first order diffraction to emulate the reflective properties of a convex spherical mirror when performing null tests with a phase-shifting interferometer. The hologram, comprised of concentric reflective rings (much like a Fresnel zone plate), is written lithographically and offers a higher degree of precision, at lower cost, than its spherical mirror counterpart and many other potential measurement techniques.
Method of determining Gaussian parameters for zoom systems with multiple moving lens groups
Yongtian Wang, Liqin Zhang, Lin Li
A new computable method of determining Gaussian parameters of zoom systems with multiple moving lens groups is presented. In the method, the lens groups are no longer divided as zoom group(s) and compensating group(s). Displacements and focal lengths of all the moving lens groups are taken as variables in optimization, and the Gaussian parameters are solved for all the zoom positions simultaneously, with the F-number of each lens group constrained to a rational value. A test program is developed using the algorithm. The results of a design example show that the method is practical and it is a step toward intelligent computer-aided design (ICAD) of zoom systems.
Lithography Systems
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Overview of optical systems for 30-nm-resolution lithography at EUV wavelengths
Russell M. Hudyma
This paper will present and compare several proposed high numerical aperture Extreme Ultraviolet Lithography (EUVL) projection systems designed for 30 nm resolution.
Influence of multilayers on the optical performance of extreme-ultraviolet projection systems
Extreme UltraViolet (EUV) projection systems consist of reflective optics, as the 13.4 nm illuminating radiation is highly absorbed in all materials. The reflectors are multilayers, which typically consist of alternating layers of molybdenum and silicon. The multilayers entail important consequences for the imaging properties, such as resolution, depth of focus and tolerances. To incorporate the influence of multilayers in optical design software an approach using the effective reflective depth is proposed. A new method to calculate the spatially varying optimum thickness of multilayers ('grading') is presented.
Development of dioptric projection lenses for DUV lithography
Advanced dioptric projection lenses from Carl Zeiss are used in some of the world's most advanced deep ultraviolet projection lithography systems. These lenses provide a resolution of better than 100 nm across the entire field of view with a level of aberration control that maximizes critical dimension uniformity and lithographic process latitude. These dioptric projection lenses are currently being used for critical layer device patterning for a wide array of complex logic, memory, and application specific integrated circuits. Zeiss' involvement in the develop of ultraviolet lenses goes back to the year 1902, exactly 100 years ago, when Moritz von Rohr calculated the first monochromatic ultraviolet micro-objectives for ultra-high resolution microphotography using a line-narrowed source. The modern dioptric projection lenses for lithography are influenced by the collective experience in the field of microscopy, and the more recent experience with early step-and-repeat lenses. This paper discusses some of the foundations of modern dioptric designs in the context of this history, demonstrating that rapid synthesis of designs is possbile using combinations of monochromatic microscope objectives and early step-and-repeat lenses from the 1970's. The problems associated with ultra high numerical aperture objectives are discussed. Specifically, it is demonstrated that aspheres can be used effective to reduce the volume of full field projection lenses, making the mechanical implementation of a 0.90 NA lens feasible in production. Several contemporary dioptric projection lens designs are reviewed in detail. The extension of these designs to numerical apertures greater than 1.0 using immersion techniques is demonstrated. These immersion lenses give the potential for 40 nm resolution.
Microlithographic lens for DUV scanner
This paper describes several kinds of new technologies introduced into the latest microlithographic lens system for Nikon's DUV (Deep Ultra Violet) scanner.
High-NA projection lens design for exposure tools
Toshiro Ishiyama, Kotaro Yamaguchi
In the history of the semiconductor industry, exposure tools have been improved in resolution. This paper describes how to increase NA of projection lens up to more than 0.7 without increasing lens diameter or deteriorating the aberrations.
Optical Design Theory
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Beyond spot diagrams: end-user-oriented optical design
In this talk, two examples are given of the process of translating user requirements into optimization and assessment tools. In the first place, recent work on the effects of aberrations on the perceived image quality of visual instruments is reviewed. This allows the assessment of a visual system in terms of expected loss of contrast and resolution as a function of aberration, and also the formulation of an image quality metric suitable for automatic optimization. The second example concerns the extraction of accurate spectroscopic information from pushbroom imaging spectrometers. It is shown how the user requirements for calibration translate into spectral and spatial uniformity of response, and further to the complete absence of spectral and spatial distortion, as well as to the minimization of the variation of the LSF width in both directions, spatial and spectral. Techniques for accomplishing this in practice, both in terms of merit function and in terms of fabrication and assembly, are also discussed.
The Holy Grail of ray-based optical modeling
Gregory W. Forbes, M A Alonso
Our new method for optical modeling puts ray optics on a more solid foundation. This method not only delivers higher accuracy, but also offers estimates of its own errors. The conceptual framework is fully consistent with intuitive interpretations of rays and avoids the ad hoc leaps of standard ray-based modeling. These include problems in such areas as propagation, refraction, reflection, and diffraction. The model's higher accuracy also means that more applications now fall within the sope of ray-based system analysis. This is demonstrated via a simple example involving a waveguide with a smoothly varying refractive index. In particular, a low-order waveguide mode is modeled as it propagates to, and interacts with, a flat interface between the waveguide and a homogeneous medium.
Inhomogeneous polarization in optical system design
It has long been understood that high numerical aperture optical systems exhibit polarization inhomogeneities in the focal plane. We take a particular interest in high NA systems with illumination which is inhomogeneously polarized in the pupil plane. Such systems may have a variety of different polarization distributions in the image plane; these polarizations need not be transverse to the optical axis, and some of the most interesting cases contain a central diffracion-limited spot which is polarized along the optical axis. This paper will describe experiments demonstrating this type of illumination in imaging and discuss the creative use of inhomogeneously polarized illumination in optical system design, emphasizing applications to microscopy/inspection and lithography.
MTF optimization by automatic adjustment of aberration merit function
I present a fast MTF optimization method. In this MTF optimization the aberration merit function is optimized. The basic concept of this MTF optimization is to connect the improvement of the aberration merit function to the improvement of the MTF merit function. The target values and weights of aberration target functions are automatically adjusted in order that the improvement of the aberration merit function is also linked to the improvement of the MTF merit function. Through exmaples it is shown that the MTF optimization used with the global optimization is effective to find good solutions as to the MTF merit function.
Local optimization strategies to escape from poor local minima
Three local optimization strategies to escape from a local minimum are discussed. The first strategy is to radically modify the error function. The old and new error function should both tend to zero for ideal systems but must differ sufficiently from another. The second strategy is to temporarily over-design the system, i.e. to make available for optimization more system parameters than a designer would normally use for the given aperture and field specifications. Finally, it is shown that, with a small enhancement of the local optimization algorithm, it is possible to move from one local minimum into a neighboring one by locating a saddle point between them.
Large-Telescope Technology
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Criteria for correction of all aberrations with quadratic field dependence
Chunyu Zhao, James H. Burge
Aberrations of imaging systems can be described using a polynomial expansion of the dependence on field position. Aberrations on axis and those with linear field dependence can be calculated and controlled using Fermat's principle and the Abbe Sine Condition. We now present a powerful new set of relationships that fully describe the aberrations that depend on the second power of the field. A simple set of equations, derived using Hamilton's characteristic functions, which we call the Pupil Astigmatism Criteria, use on-axis behavior to evaluate and control all aberrations with quadratic field dependence and arbitrary dependence on the pupil. These relations are explained, validated, and applied to design optical systems that are free of all quadratic field dependent aberrations.
Basic principles in the optical design of imaging multiple aperature systems
Erin M. Sabatke, James H. Burge
We discuss the basic concepts that have been useful in our work designing multiple aperture telescopes with wide fields of view. We examine combining errors at zero field and errors that are linear as a function of field. An easy optimization for satisfying the sine condition to eliminate linear piston errors is given. Methods for estimating the RMS wavefront errors for the lower-order combining errors are given.
OSIRIS optical design
The Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) is a first generation instrument for the 10.4-m Gran Telescopio Canarias (GTC) that will be operational in mid-2004. On such a large telescope, OSIRIS is the first instrument to use tunable filters, combined with charge shuffling capabilities, covering the wavelength range (365 - 1000 nm). To be installed first at a Nasmyth platform, OSIRIS is also compact enough to fit in the Cassegrain focus envelope. This paper discusses the OSIRIS optical design process based on the classical collimator plus camera focal reducer configuration concept. To provide a wide mode and resolution versatility, several combinations of grisms, color, order sorter, interference and tunable filters are attainable in the collimated beam, near the pupil. The OSIRIS geometry, specifications, features, and performance are briefly discussed. Subsection (#5) is centered on the pupil size to calculate angular magnification and collimator FOV. These values are compared with those taken from similar instruments for 6.5-m to 10-m telescopes. This contribution is meant to share our experience on the optical design issue with colleagues not necessarily familiarized with astronomical instrumentation design. A previous approach on the OSIRIS optical design and two more general descriptions are available.
Illumination Systems
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Illumination optimization: The revolution has begun
Over the last 35 years, optimization of imaging systems has become commonplace. With the advent of powerful illumination software design packages, the industry is poised for illumination optimization. Trends and examples will be provided.
Enhancement of the downhill simplex method of optimization
The downhill simplex method of optimization is a "geometric" method to achieve function minimization. The standard algorithm uses arbitrary values for the deterministic factors that describe the "movement" of the simplex in the merit space. While it is a robust method of optimization, it is relatively slow to converge to local minima. However, its stability and the lack of use of derivatives make it useful for optical design optimization, especially for the field of illumination. This paper describes preliminary efforts of optimizing the performance of the simplex optimizer. This enhancement is accomplished by optimizing the various control factors: alpha (reflection), beta (contraction), and gamma (expansion). This effort is accomplished by investigating the "end game" of optimal design, i.e., the shape of the figure of merit space is parabolic in N-dimensions near local minima. The figure of merit for the control factor optimization is the number of iterations to achieve a solution in comparison to the same case using the standard control factors. This optimization is done for parabolic wells of order N equals 2 to 15. In this study it is shown that with the correct choice of the control factors, one can achieve up to a 35% improvement in convergence. Techniques using gradient weighting and the inclusion of additional control factors are proposed.
Source modeling and calculation of mask illumination during extreme-ultraviolet lithography condenser design
Lenny Laughlin, Jose M. Sasian
Lithography condensers must create very uniform illumination at the mask plane. The non-uniformity in the illumination is required to be less than 1%. To meet this requirement a designer must use a method for determining the illumination created on the mask plane during the design of the condenser system. This paper describes a method for calculating the illumination at a plane in a lithography condenser system. This method is a general one that is applicable to many systems besides those for extreme ultraviolet lithography (EUVL). Our methodology uses reverse ray tracing to accurately and efficiently determine illumination in a system during the design phase. The technique is used with a standard optical design software package. This enables the system designer to test the illuminaton uniformity of the design with the same software that is used for the design work itself. Therefore, the user is not required to use illumination specific software to model the illumination properties for the design. Implementation of this new methodology necessitates accurate modeling of a source in the optical design software. The technique for modeling sources using apodization files is described. Results are shown for point sources, multiple point source configurations, and finite sources that have non-trivial surface radiance distributions. In some cases, the results of our method are compared to those found using a traditional technique of calculating illumination.
3D NURBS representation of surfaces for illumination
Use of NURBS surfaces to create facets on a reflecting surface will be considered. Specifically, the design of a reflector that generates a circular illuminance pattern will be investigated. Important considerations are: choice of variables used to represent a NURBS surface, total number of variables, parameterization and/or knot vector specification, and where to use algorithmic vs. optimization approaches.
A fly's eye condenser system for uniform illumination
Blake G. Crowther, Donald G. Koch, Joseph M. Kunick, et al.
We recently completed a preliminary design of a novel illumination system. The concept of this design is to integrate the incident irradiance from a small source such that an otherwise non-uniformly iluminated target is uniformly illuminated, while maintaining high radiometric throughput. Our design incorporates a collector to efficiently gather flux from the source, two multi-element faceted arrays, and a flux relay. We explore the concept behind our design and show a preferred embodiment and its predicted peformance.
NIF and IR Optical Systems
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National Ignition Facility end-to-end beamline optical model
Ronald J. Korniski, Janice K. Lawson
The optical model of a National Ignition Facility beamline will be described and illustrated. The complexity ofthe optical design will be evident. The benefits of having an Endto-End optical model will be presented.
Infrared optic using polymer-layered lens
It was previously reported that a midwave infrared (IR) imager with silicon lenses and a flat laminated plastic surface had been made. It had a focal length of 50 mm and f/# of 2.6. This paper updates the progress of the developing prototype with MTF, transmission measurements, and a design philosophy for strong absorptions regions in a material.
Optical design of CPAPIR, a cryogenic IR camera for OMM
The optical design of the wide-field infrared camera CPAPIR (Camera PAnoramique Proche InfraRouge) for the Mont Megantic Observatory (OMM) has been completed. CPAPIR will be a unique wide-field camera at the OMM. It has a full field of view of 0.71 degrees, an instantaneous field of view of 0.88 arc-seconds, and a spectral coverage of 0.85 - 2.5 μm. The camera is operated under vacuum and at cryogenic temperature. The performance (image quality, vignetting, cold stop efficiency, ghost analysis and tolerancing) of CPAPIR has been optimized at cold temperature using cryogenic indices of refraction and coefficients of thermal.
Step-zoom dual-field-of-view IR telescope
Muhammad Nadeem Akram, Muhammad Hammad Asghar
In this paper, the design of a dual field-of-view telescope for 8 - 12 μm imaging waveband is described. Preliminary calculations are done to determine the first-order parameters of the narrow and wide-field modes. To achieve a switchable dual field-of-view system, an optical configuration based on the axial motion of a single lens group along the optical axis is used. The same lens is also used for focusing at near objects and for athermalization by very small axial movement. A total of 6 lenses with one conic surface are used in the design making it cost effective and lightweight. The final optical design is presented along with the aberrations curves and the MTF plots showing excellent performance in both field-of-views.
National Ignition Facility beamline pupil relay plane locations and imaging
Ronald J. Korniski, Janice K. Lawson
Axial astigmatism can be introduced into the nominal design of an optical system by tilted and tilted-wedged plates. The pupil images in the National Ignition Facility experience many such components. Some ramifications will be explored.
Diffraction and Beam Propagation
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Optical design and fabrication in China
In recent years, the Chinese optical industry has been growing with an amazing speed, in the forms of joint ventures, private enterprises and government supported investments. The current status of optical design and fabrication in China is outlined. Optical design software packages commonly used in the country are listed and their features summarized. Example manufacture capacities are given for typical companies in areas including optical glasses, lens elements and commercial products such as telescopes, microscopes, camera lenses, etc. Recent developments such as aspheric lens fabrication and diffractive element study are briefed. Efforts made in Beijing Institute of Technology to promote closer and more convenient international cooperation in optical industry are described.
Optical design of laser beam shaping systems
An overview of the history and current practices of laser beam shaping is presented. When diffraction effects are not important, geometrical methods for laser beam shaping (ray tracing, conservation of energy within a bundle of rays, and the constant optical path length condition) can be used to determine system configurations, including aspheric elements and spherical-surface GRIN lenses, which are required to change the intensity profile into a more useful form. Geometrical optics-based design methods are presented for shaping both rotationally and rectangular symmetric laser beam profiles. Applications of these techniques include design of a two-plano-aspheric lens system for shaping a rotationally symmetric Gaussian beam, a two-mirror system with no central obscuration for shaping an elliptical Gaussian input beam, and a three-element GRIN system for shaping a rotationally symmetric Gaussian beam.
Practical considerations for simulating beam propagation: a comparison of three approaches
Bryan D. Stone, Thomas J. Bruegge
Conventional ray tracing cannot always adequately model propagation of optical beams. We compare three approaches for modeling diffraction effects throughout an optical system: (1) FFT-based, (2) Gaussian beam decomposition, and (3) the SAFE method of Forbes and Alonso. The basic idea behind each method is described and some simple examples are given that highlight the main features of each method.
General beam propagation through non-orthogonal optical systems
Michael E. Harrigan
The methods of propagation of simple paraxial Gaussian beams through rotationally symmetric optical systems have long been established. A theoretical method for the propagation of Gaussian beams through non-orthogonal optical systems has been published and generalized for non-Gaussian beams, but the combined capability has not been widely implemented. To design and build optical systems using lasers and cylindrical optics, it is important to have these computational tools available. In this paper, the theory will be reviewed and the mathematical details of its practice will be given. Some aspects of beams with general astigmatism will be presented. For example, the theory explains in detail how a circular Gaussian beam will be converted into a rotating elliptical beam after passing through crossed cylinder lenses. An example of such a system will be discussed and measurements compared to the predicted results.
Some thoughts on scalar diffraction theory
Hiroshi Ooki
Lens designers are required to design the nearly aberration-free optics in order to meet the extremely high specification of the system. Besides the wavefront aberration generated by the lens, we should understand that an image degradation is introduced not only by the lens but also on the object or image plane. This means that the aberration-free image is not the ideal image. This discrepancy is described considering the vector nature of the light.
Conformal Optics, PALs, and Eye Modeling
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Fundamentals of conformal dome design
David J. Knapp
No abstract.
I like your GRIN: design methods for gradient-index progressive addition lenses
Progressive addition lenses (PALs) are vision correction lenses with a continuous change in power, used to treat the physical condition presbyopia. These lenses are currently fabricated using non-rotationally symmetric surfaces to achieve the focal power transition and aberration control. In this research, we consider the use of Gradient-Index (GRIN) designs for providing both power progression and aberration control. The use of B-Spline curves for GRIN representation is explained. Design methods and simulation results for GRIN PALs are presented. Possible uses for the design methods with other lenses, such as unifocal lenses and axicons, are also discussed.
Designing a perfect cornea: computational aspects
Jacob Rubinstein, Gershon Wolansky
We analyze an algorithm for the design of a perfect cornea that exactly focuses a preselected object or a preselected wave front on the retina. The algorithm can be used, for example, in refractive surgery. We consider the sensitivity of the algorithm to various errors, including errors in the measurements of the aberrations, the original corneal topography and the ablation process.
Eye rotation and vignetting in visual instruments with a real exit pupil
Martha Rosete-Aguilar, Juan L. Rayces
This paper analyses the effect of vignetting in visual instruments with a real exit pupil due to the rotation of the eye. The analysis of vignetting is made under a paraxial approximation and in the tangential plane only.
Photonics Systems
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Stress birefringence modeling for lens design and photonics
Modeling the effects of stress birefringence is critical for polarization sensitive optical systems. Optical design and optomechanical software tools to model stress birefringence are discussed and illustrated for three examples. The first example compares retardance in calcium fluoride lenses as a function of shape. The second example discusses the modeling of a beam splitter in an LCD projector. Lastly, stress birefringence modeling tools are demonstrated in detail in the design of focusing and collimating lenses for a WDM wavelength selective switch. The wavelength selective switch, operating over the telecom C-band (1530-1561nm), employs a liquid crystal polarization modulator to select the output fiber for each input channel. Over the operational temperature range, CTE mismatches between the glasses and mounting materials induce stress in the optical elements creating cross-talk between the output optical fibers. Cross-talk is computed as a function of temperature for several potential design concepts.
Tolerantly designed optical clock distribution system
Juergen Jahns, B. Lunitz, Markus Stoelzle
The influence of process parameters in the design and fabrication of a clock distribution system using integrated free-space optics are considered based on ray-tracing simulations and experiments.
Analysis of near-field characteristics of a diffractive optical laser beam profile shaper using a high-accuracy finite difference time domain method
The finite-difference time-domain (FDTD) method as realized in the Yee algorithm is very useful for solving the analytically intractable diffraction problems that arise in the design of diffractive optical elements (DOE). The error, ε, of the Yee algorithm is rather large. We introduce a new high accuracy version of the Yee algorithm based on nonstandard finite differences. We have verified its performance by comparing with known analytical solutions. We have used this algorithm to study the near field (0 - 10 wavelengths) diffraction patterns of three binary phase gratings. Grating (1) has a constant period, while grating (2) has a variable one. Grating (3) is generated by interlacing grating (1) with (2). The period of grating (1) is on the order of a wavelength. Some of these computed fields display interesting and possibly useful Fourier spectra.
Porro's achromatic polarization-preserving beam displacer
It is shown that a simple achromatic polarization-preserving beam displacer can be realized in the Porro's two-prism image erector system. The theory of geometric phase and compensating phase shifting is used to illustrate the mechanism of achromatic property in the system. Tilting tolerance and the influence of material, such as CaF2 and plactic materials, are also addressed. The tilting errors of each component or totally internal reflected surface will not seriously affect the performance.
IODC Problem Session
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2002 IODC design problem: the diffractive simulator
The lens design problem for the 2002 IODC is to design a 100 mm focal length, f/8 all refractive system which simulates the chromatic behavior of a diffractive optical element. The lenses must be all spherical and be made of Schott glasses only. There is no restriction on the number of lenses, the design form, or the length of the overall lens. The merit function comprises the rms spot size at a nominal wavelength and the rms of the focal shift differences between the refractive lens and those of the 100 mm, f/8 diffractive optical element. There were forty two entries to the contest; in general, the results were quite good, with most of the spot sizes well below the diffraction limit, and with the rms focal shift differences being much less than 0.001 mm.
Poster Session
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Design and modeling of a dual-magnification Galilean IR telescope and associated focusing optics
Muhammad Nadeem Akram, Muhammad Hammad Asghar
In this paper, the complete design and modeling of a dual-magnification 8 - 12 μm infrared Galilean telescope along with the associated focusing optics and scanning mechanism is described. Preliminary calculations are done to determine the first-order parameters of the narrow and the wide-field modes. Initially, the telescope (narrow and wide-angle modes) and the focusing optics are designed as individual subsystems. Later, they are combined together and the complete optical system is modelled and optimized as one unit to get the required final performance. It is shown that this final optimization step is very important to access the overall performance of the complete system. We can actually reduce the total number of lenses or the number of conic surfaces used in the final system by modelling and optimizing it as one unit. This reduces the cost and the complexity of the overall system. The final optical designs along with their aberrations curves and MTF plots are presented showing excellent performance in both the high and the low magnification modes.
Design and modeling of optical engine for LC rear-projection display
Zhicheng Weng, Zengbao Zhang
Based on analyzing the LC rear projective TV system, The OE (optical engine) for three penal LCoS rear projection TV system has been designed and modeled, The OE (optical engine) of LC rear projection display is the main component of the system, and it directly affects final performance, so the design of good color performance, high brightness and contrast and high optical efficient is the key of the system. From a commercial viewpoint, a compact size and light weight design makes it more competitive. LightTools software has a great many of powerful functions, such as modeling of optical system, analysis of illumination, modeling of machine structure, analysis of polarization and design of optical coating. We have used LightTools to analyses and optimize a whole optical engine of three penal LCoS projection display including illumination system, dividing and recombining of colors system, projection lens. At the end evaluated the performances of optical engine (parameters of output, uniformity, contract, resolution and so on).
Design of a wide-angle fast optical system with anamorphic mirrors
Takayuki Nakano, Yasuhisa Tamagawa
All-reflective systems have been applied to optical systems because of less material limitations compared with refractive systems. The key to design an all-reflective system is how to widen the field view and the aperture without obscurations of the rays by the mirrors. In order to avoid the obscurations, many systems have been designed to work off-axis with respect to the field angle, which show rotational asymmetry around the optical axis. In this paper, we propose a design method adapted effectively to this asymmetry by use of anamorphic mirrors and an elliptic aperture. In our method two main design factors, placement of mirrors and enlargement of the aperture, are separately optimized. We show a design example of a three-mirror system reaching an F-number of 1.2 with 18×14 degrees field angle.
Nulling interferometry with a single-element phase-shifting interferometer
Nulling interferometry based on a single-element (liquid-crystal-phase-retarder) phase-shifting interferometer is proposed and analyzed with optical simulation. The geometric-phase-based nulling interferometry is also reinvestigated for comparison.
Untold secrets of macro language usage in optical design
Shiyu Zhang
Macro languages are included in optical design software to enable the designer to expand the functions of the software. This paper reveals the untold secrets of macro language usage in optical design through several examples.
Mercado/Robb/Buchdahl coefficients: an update of 243 common glasses
Michael Bolser
The 1983 Mercado/Robb listing of Buchdahl chromatic coordinate coefficients is supplemented with glasses from the Schott and O'Hara catalogues. The coefficients were calculated by using Buchdahl's cubic model. Appropriately selected materials yield a superachromat.
Research for uniform illumination systems
Yifan Huang, Lin Li, Liansheng An, et al.
Methods of getting uniform illumination are introduced in this paper. Studies on a new optical components -- Rod lens are carried out and rules of its uniformity changing with respect to its size are deduced.
Research on CCD intersection measuring techniques in detecting multiple targets
Menghong Feng, Lin Li, Yifan Huang, et al.
A new method of CCD intersection measurement in detecting multiple targets is discussed, and the math-model for the coordinate measurement of CCD is set up. This method is different from conventional measurement method in that it is able to detect many targets at the same time according to diverse gray level. And this model can improve the measurement accuracy and increase computing speed.
Design of a complex optical system for measuring vibrant track of cable crossing river
In order to measure the vibrant track of a cable crossing a river, a complex optical system is introduced to realize the image of a rectangle on a CCD image surface. The quantitative diagnosis of the system's aberrations reveals that the distortion is beyond the tolerance. A new and accurate method of digital correcting the distortion with asymmetrical distribution is proposed.
Discretization effects on imaging performance of digital holographic systems
Lei Xu, Xiaoyuan Peng, Jianmin Miao, et al.
The imaging capacity of a digital holographic system is studied with space-bandwidth product. The analyses demonstrate that an in-line arrangement can achieve better performance in both the effective field of view and imaging resolution. Furthermore, the effects introduced by the discrete feature of a CCD sensor, characterized by the pixel amount and pixel sensitive dimensions, to the image formation and quality are studied. Comparative discussions are given to the in-line and off-axis geometries respectively.
Comparative study on thermal effects of diode-pumped Nd:YVO4 and Nd:YAG lasers
The thermal effects of diode-pumped Nd:YVO4 and Nd:YAG lasers are analyzed by a one-dimensional model and a three-dimensional model, respectively. The characteristics of the Nd:YVO4 and Nd:YAG rod are comparatively discussed, which include temperature distributions and thermal lensing effect. The model takes into account of index parts and end effect. The theoretical analyses provide a good prediction for the thermal lensing of diode-pumped Nd:YVO4 and Nd:YAG lasers.
Effect of fine undulation of lens surface on the optical performance
Masato Shibuya, Kouichi Aoyagi, Suezou Nakadate, et al.
The effect of residual fine undulation on aspherical suface may not be always evaluated correctly. We make this problem clear both theoretically and numerically and proposed the simple and valuable equation for evaluating the fine undulation.
Rapid computation of return loss in CODE V
Byron B. Taylor
Presented is a macro running in CODE V that automatically calculates the return loss from all surfaces in a lens system using a Gaussian beam approach. Results are compared with output from a diffraction-based beam propagator and a ray based Gaussian beam apodization approach.
FOCOIVA lens: scanner in lateral and longitudinal directions
Sergio Vazquez-Montiel, Tetsuya Suzuki, Morio Hosoya
We propose a novel optical system that can scan simultaneously in perpendicular and longitudinal directions to the optical axis, which we have named the FOCOIVA lens system. We give the equations for the first order analysis and also the equations of motion for the lenses. Examples calculated with these equations are presented and finally we give the optical design for the writing system that will be used for a reader of digital documents.
Lens Design
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Miniature injection-molded optics for fiber optic in vivo confocal microscopy
In collaboration with the Department of Biomedical Engineering at the University of Texas at Austin and the UT MD Anderson Cancer Center, a laser scanning fiber confocal reflectance microscope (FCRM) system has been designed and tested for in vivo detection of cervical and oral pre-cancers. This system along with specially developed diagnosis algorithms and techniques can achieve an unprecedented specificity and sensitivity for the diagnosis of pre-cancers in epithelial tissue. The FCRM imaging system consists of an NdYAG laser (1064 nm), scanning mirrors/optics, precision pinhole, detector, and an endoscopic probe (the objective). The objective is connected to the rest of the imaging system via a fiber bundle. The fiber bundle allows the rest of the system to be remotely positioned in a convenient location. Only the objective comes into contact with the patient. It is our intent that inexpensive mass-produced disposable endoscopic probes would be produced for large clinical trials. This paper touches on the general design process of developing a miniature, high numerical aperture, injection-molded (IM) objective. These IM optical designs are evaluated and modified based on manufacturing and application constraints. Based on these driving criteria, one specific optical design was chosen and a detailed tolerance analysis was conducted. The tolerance analysis was custom built to create a realistic statistical analysis for integrated IM lens elements that can be stacked one on top of another using micro-spheres resting in tiny circular grooves. These configurations allow each lens element to be rotated and possibly help compensate for predicted manufacturing errors. This research was supported by a grant from the National Institutes of Health (RO1 CA82880). Special thanks go to Applied Image Group/Optics for the numerous fabrication meetings concerning the miniature IM objective.