Proceedings Volume 8129

Novel Optical Systems Design and Optimization XIV

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Proceedings Volume 8129

Novel Optical Systems Design and Optimization XIV

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Volume Details

Date Published: 9 September 2011
Contents: 7 Sessions, 24 Papers, 0 Presentations
Conference: SPIE Optical Engineering + Applications 2011
Volume Number: 8129

Table of Contents

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Table of Contents

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  • Front Matter: Volume 8129
  • Plenary Session
  • Imaging Systems
  • Biomedical Applications
  • Simulation and Metrology
  • Nonimaging and Freeform Optics
  • Poster Session
Front Matter: Volume 8129
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Front Matter: Volume 8129
This PDF file contains the front matter associated with SPIE Proceedings Volume 8129, including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.
Plenary Session
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The history of telescopes and binoculars: an engineering perspective
John E. Greivenkamp, David L. Steed
The design of the refracting telescope advanced rapidly following its invention in 1608, reaching its modern configuration in about a century. Even though the development of binoculars began almost simultaneously, nearly three hundred years elapsed before practical prismatic binoculars became available. The impediments to practical binoculars were not only in optical design, but in mechanical design, manufacturing, and materials. This paper will document the history of telescopes and binoculars from an engineering perspective looking at the evolution of basic optical system layout as well as some of the mechanical issues faced. This development will be illuminated using examples from the Museum of Optics at the College of Optical Sciences at the University of Arizona.
Imaging Systems
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3D astigmatic depth sensing camera
Gabriel C. Birch, J. Scott Tyo, Jim Schwiegerling
Three-dimensional displays have become increasingly present in consumer markets. However, the ability to capture threedimensional images inexpensively and without major modifications to current cameras is uncommon. Our goal is to create a modification to a common commercial camera that allows a three dimensional reconstruction. We desire such an imaging system to be inexpensive and easy to use. Furthermore, we require that any three-dimensional modification to a camera does not reduce its resolution. Here we present a possible solution to this problem. A commercial digital camera is used with a projector system with astigmatic focus to capture images of a scene. By using an astigmatic projected pattern we can create two different focus depths for horizontal and vertical features of the projected pattern, thereby encoding depth. This projector could be integrated into the flash unit of the camera. By carefully choosing a pattern we are able to exploit this differential focus in image processing. Wavelet transforms are performed on the image that pick out the projected pattern. By taking ratios of certain wavelet coefficients we are able to correlate the distance an object at a particular transverse position is from the camera to the contrast ratios. We present our information regarding construction, calibration, and images produced by this system. The nature of linking a projected pattern design and image processing algorithms will be discussed.
3D imaging with a single-aperture 3-mm objective lens: concept, fabrication, and test
Ronald Korniski, Sam Y. Bae, Michael Shearn, et al.
There are many advantages to minimally invasive surgery (MIS). An endoscope is the optical system of choice by the surgeon for MIS. The smaller the incision or opening made to perform the surgery, the smaller the optical system needed. For minimally invasive neurological and skull base surgeries the openings are typically 10-mm in diameter (dime sized) or less. The largest outside diameter (OD) endoscope used is 4mm. A significant drawback to endoscopic MIS is that it only provides a monocular view of the surgical site thereby lacking depth information for the surgeon. A stereo view would provide the surgeon instantaneous depth information of the surroundings within the field of view, a significant advantage especially during brain surgery. Providing 3D imaging in an endoscopic objective lens system presents significant challenges because of the tight packaging constraints. This paper presents a promising new technique for endoscopic 3D imaging that uses a single lens system with complementary multi-bandpass filters (CMBFs), and describes the proof-of-concept demonstrations performed to date validating the technique. These demonstrations of the technique have utilized many commercial off-the- shelf (COTS) components including the ones used in the endoscope objective.
Wide and narrow dual image guidance system for ground vehicle on fast focusing and stereo matching operation
Akira Akiyama, Nobuaki Kobayashi, Eiichiro Mutoh, et al.
We have developed the wide and narrow dual image guidance system for ground vehicle on fast focusing and stereo matching operation. The fast focusing catches the distance information of outside world. The stereo matching operation on the focused two wide images finds the characteristic position to detect the fine distance information through the fast focusing using the narrow images due to the camera with the long focal length. Our fast focusing algorithm works precisely on the differential image such as the Daubechies wavelet transformed high pass image, the Roberts image, Prewitt image, Sobel image and the Laplacian image. After the stereo matching operation on the focused wide images, the two cameras serves the narrow image focusing operation. This procedure establishes the reliability of the detection of the object and gives the fine image information of the object. The pointing operation of the long focal length camera of the narrow image uses the related pixel address information due to the stereo matching and the 2 axes gimbal equipment of the precise resolution. We experimented the detection of the object by stereo matching and ranging the fine distance by narrow image focusing. The experiment gives the appropriate detection and fine pointing of the narrow image focusing to meet the guidance capability of the ground vehicle.
Reflective autofocus image system with MEMS deformable mirror and freeform design
In this paper, we proposed a miniature auto-focus image system without moving components. We had previously presented a 2-Mega-Pixel auto-focus module by combining reflective optics, refractive optics and MEMS deformable mirror. This configuration can be further improved. We expanded 2-Mega-Pixel image plane to 8-Mega-Pixel image plane and corrected the aberration by adding one more lens as a stop. For the concern of the cost, we distributed the optical power of the adding lens to the fixed reflecting mirror and the deformable mirror, and we designed them as freeform surfaces to compensate aberrations. Finally, an 8M pixel auto-focus image system that FOV is ±26° can be achieved. The MTF at half spatial frequency is above 25% , and the thickness of the system is 8.2mm.
Continuous optical zoom module based on two deformable mirrors for mobile device applications
Yu-Hung Lin, Guo-Dung J. Su
In recent years, optical zoom function of the mobile camera phones has been studied. However, traditional systems use motors to change separation of lenses to achieve zoom function, suffering from long total length and high power consumption, which is not suitable for mobile phones use. Adopting MEMS polymer deformable mirrors in zoom systems has the potential to reduce thickness and have the advantage of low chromatic aberration. In this paper, we presented a 2X continuous optical zoom systems for mobile phones, using two deformable mirrors, suitable for 5-Mega-pixel image sensors. In our design, the thickness of the zoom system is about 11 mm. The smallest EFL (effective focal length) is 4.7 mm at full field angle of 52° and the f/# is 4.4. The longest EFL of the module is 9.4 mm and the f/# is 6.4.
Biomedical Applications
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Development of low-coherence light sheet illumination microscope for fluorescence-free bioimaging
Light Sheet Illumination Microscopy (LSIM) is an imaging modality featuring the novel arrangement with the illumination axis perpendicular to the detection axis. In this technology a well defined light sheet is generated and aligned precisely to the focal plane of the microscope objective and thus only the thin in-focus layer of the sample is illuminated and imaged, thereby avoiding out-of-focus light. Besides the inherent optical sectioning function, other advantages include fast imaging speed, high longitudinal resolution and decreased light-induced damage. Though promising, this microscopy is currently restricted to imaging fluorescently labeled tissue; in inspection of intact tissue using scattered light, the acquired images suffer from intense speckles because of the severe coherence in the illumination. This work aims to build a microscope capable of achieving intrinsic images of the fluorescence-free sample with reduced or eliminated speckles, by developing a low coherence light sheet illumination. To diminish the spatial coherence, the sample is illuminated with tens of independent sub-beams (without inter-coherence) illuminating the FOV (Field Of View) of the microscope with diverse incident angles. The temporal coherence is dramatically reduced by employing a supercontinuum laser with a broad spectrum as the light source. The new microscopy significantly extends the functionality of Light Sheet Illumination Microscopy and will enable many new bioimaging applications.
Design of a retinal tracking system for jumping spiders
Cristina Canavesi, Skye Long, Dennis Fantone, et al.
We designed an optical system for tracking the retinal movement of a jumping spider as a stimulus is presented to it. The system, using all off-the-shelf optical components except for one custom aspheric plate, consists of three sub-systems that share a common path: a visible stimuli presentation sub-system, a NIR illumination sub-system, and a NIR retinal imaging sub-system. A 25 mm clearance between the last element and the spider ensures a stable positioning of the spider. The stimuli presentation system relays an image from a display to the spider eye, matching the 15 arcmin resolution of the two principal eyes and producing a virtual image at a distance of 255 mm from the spider, with a visual full field of view of 52°. When viewing a stimulus, the spider moves its retinas, which cover a full field of view of only 0.6°, and directs them to view different places in the visual field. The retinal imaging system uses a NIR camera to track changes of 0.5° in the field of view seen by the spider. By tracking retinal movement across images presented to spiders, we will learn how they search for visual cues to identify prey, rivals, and potential mates.
SOI strip waveguide microring resonator for homogeneous biosensing
We report the simulation and analytical results obtained for homogenous or bulk sensing of protein on Siliconon- insulator strip waveguide based microring resonator. The radii of the rings considered are 5 μm and 20 μm; the waveguide dimensions are 300 × 300 nm. A gap of (i) 200 nm and (ii) 300 nm exists between the ring and the bus waveguide. The biomaterial is uniformly distributed over a thickness which exceeds the evanescent field penetration depth of 150 nm. The sensitivities of the resonators are 32.5 nm/RIU and 17.5 nm/RIU (RIU - Refractive index unit) respectively.
Simulation and Metrology
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Scalability of a cross-platform multi-threaded non-sequential optical ray tracer
The GelOE optical engineering software implements multi-threaded ray tracing with just a few simple cross-platform OpenMP directives. Timings as a function of the number of threads are presented for two quite different ZEMAX non-sequential sample problems running on a dual-boot 12-core Apple computer and compared to not only ZEMAX but also FRED (plus single-threaded ASAP and CodeV). Also discussed are the relative merits of using Mac OSX or Windows 7, 32-bit or 64-bit mode, single or double precision floats, and the Intel or GCC compilers. It is found that simple cross-platform multi-threading can be more efficient than the Windows-specific kind used in the commercial codes and who's the fastest ray tracer depends on the specific problem. Note that besides ray trace speed, overall productivity also depends on other things like visualization, ease-of-use, documentation, and technical support of which none are rated here.
Modeling the role of phosphor grain packing in compact fluorescent lamps
N. Pannier, M. Filoche, M. Plapp, et al.
Compact fluorescent lamps contain mercury gas which generates ultraviolet radiation. A thin powder layer constituted of rare-earth oxides is coated inside the glass tube. The role of this layer is to convert the inside ultraviolet radiation into outside visible radiation. We focus here on a particular powder layer, constituted by phosphor grains. The phosphor layer has to achieve two distinct goals. On the one hand the grains have to absorb the maximum amount of ultraviolet radiation in order to generate visible light, and on the other hand the transmission of visible light has to be maximized in order to optimize the efficiency of the compact fluorescent lamp. Here, we study the influences of grain size, grain shape, density of packing powder, and thickness of the phosphor coating. Such a study is a first step towards a better understanding of the conversion efficiency of ultraviolet radiation into visible radiations, and can eventually, help to improve the production line of compact fluorescent lamps. All the presented simulations were performed with the commercial software LightTools® using a ray tracing method.
Simulation and optimization of a sub-micron beam for macromolecular crystallography using SHADOW and XOP at GM/CA CAT at the APS
Zunping Liu, Shenglan Xu, Derek W. Yoder, et al.
The small, high intensity and low convergence beams available on beamlines at 3rd generation synchrotron sources have been a boon to macromolecular crystallography. It is now becoming routine to solve structures using a beam in the 5 - 20 micron (FWHM) range. However, many problems in structural biology suffer from poor S/N due to small (a few microns) crystals or larger inhomogenous crystals. In additional, theoretical calculations and experimental results have demonstrated that radiation damage may be reduced by using a micron-sized X-ray beam. At GM/CA CAT we are developing a sub-micron, low convergence beam to address these issues. The sub-micron beam capability will be developed on the existing beamline 23ID-D where the minimum beam size available to users is currently 5 microns in diameter. The target goals are a beam size of ~0.8 micron (FWHM) in diameter, with a beam convergence of less 0.6 milli-rads, a flux greater than 5×1010 photons/sec, and an energy range from 5 to 35 keV. Five optical systems will be compared: 1) a single set of highly demagnifying Kirkpatrick-Baez (K-B) mirrors, 2) multiple Fresnel Zone Plates (FZP), 3) a set of K-B mirrors focusing to a secondary source that is imaged by another set of K-B mirrors, 4) a set of K-B mirrors focusing to a secondary source that is imaged by a FZP, 5) a horizontal focusing mirror focusing to a secondary source that is imaged by another horizontal mirror together with a vertical focusing mirror. Here we will present the results of a design optimization based on ray trace simulations (SHADOW), flux calculations (XOP), and experimental results on 23ID.
Determination of off-axis aberrations of imaging systems using on-axis measurements
James H. Burge, Chunyu Zhao, Matt Dubin, et al.
Imaging aberrations that have linear dependence on field angle are caused by pupil aberrations that can be described using the Abbe sine condition. This well-known relationship is frequently used to guide the design of optical imaging systems. For example, the aberration of coma is eliminated in the design of axisymmetric systems by controlling the pupil distortion, as defined by a standard implementation of the sine condition. An optical system with misalignments of surface irregularities will suffer pupil distortions that are quantified using a more generalized form of the sine condition. Such pupil aberrations create image aberrations that have linear dependence on field angle. While it is possible to infer the state of alignment by measuring multiple field points, it may be more straightforward to perform a single on-axis measurement of the sine condition violations. This paper summarizes the generalized sine condition and relationship between violations of this condition and aberrations with linear field dependence. An application is discussed for measuring sine condition violations of a 4-mirror system, which allows determination of the off-axis aberrations.
Innovating spectrometry studies at undergraduate level using a linear CCD array
Amit Garg, Reena Sharma, Vishal Dhingra
Students are less enthused in performing various spectrometry experiments in a conventional optics laboratory at the undergraduate level. In order to motivate students towards spectrometry, the present development focuses on innovating spectrometry experiments in undergraduate optics laboratory by integrating a linear CCD (Charge Coupled Device) for optical intensity capture using LabVIEW based application and a Digital Storage Oscilloscope with NI LabVIEW Signal Express. In the first step, students have calibrated wavelength in terms of x- position using a standard Mercury light source. Then this calibration has been used to display and measure the emission spectra of various light sources. Various measurements performed include characterizing various LEDs in terms of wavelengths emitted for use in measurement of Planck's constant, measuring characteristic wavelengths in emission spectra of hydrogen lamp (for calculating Rydberg's constant).
Nonimaging and Freeform Optics
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Ultracompact SWIR telephoto lens design with SMS method
In this work, we propose two new optical structures, using the Simultaneous Multiple Surfaces (SMS) method, comprised of 2 reflecting surfaces and 2 refracting surfaces, 800mm focal length, f/8 (aperture diameter 100 mm) and 1.18° diagonal field of view in the SWIR band. The lens surfaces are rotational symmetric and calculated to have good control of non-paraxial rays. We have achieved designs with excellent performance, and with total system length of less than 60 mm.
Fresnel lens solar concentrator derivations and simulations
Fresnel lens solar concentrators continue to fulfill a market requirement as a system component in high volume cost effective Concentrating Photovoltaic (CPV) electricity generation. Design and optimization may be performed using comprehensive system simulation tools, but before investing in the effort to build a complete virtual model framework, much insight can be gathered beforehand by generating a parameterized simulation cache and referencing those results. To investigate the performance space of the Fresnel lens, a fast simulation method which is a hybrid between raytracing and analytical computation is employed to generate a cache of simulation data. This data is postprocessed to yield results that are not readily achieved via derivation. Example plots that can be used for look-up purposes will be included. Lens parameters that will be interrogated include focal length, index of refraction, prism fidelity, aperture, transmission and concentration ratio. In order to compactly represent a large variety of lens configurations, some variables that define the Fresnel lens will be parameterized. Analysis will be limited to Fresnel lens prisms oriented toward the photovoltaic (PV) cell and the plano surface directed toward the sun. The reverse of this configuration is rarely encountered in solar concentration applications and is omitted.
Novel freeform optical surface design with spiral symmetry
Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. These restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern when dealing with optical design. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. The general designing procedure will be described in detail.
Optical design of light guide film with external illuminance backlight module
Chih-Ta Yen, Yi-Chin Fang, Cheng-Hsien Huang, et al.
Liquid crystal displays have many good qualities, such as ultrathinness, light weight, high brightness, and so forth. It is very important to improve the display performance of backlight module systems to provide better uniformity, brightness, lower power consumption, and lower weight. In backlight modules, the light guide plate (LGP) is a key component in reducing the cost and easier access to develop LGPs on its own. This research proposes the concept of Back Light Unit (BLU) with external illuminance. This special optical design may introduce the external light into BLU in order to improve the power-saving. One is for 14 inch monitor, which has 21% improvement. Another for 3.5 inch display might have improvement 15%.
Poster Session
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Laser-based study of geometrical optics at school level
Amit Garg, Vishal Dhingra, Reena Sharma, et al.
Students at the school level from grade 7 to 12 are taught various concepts of geometrical optics but with little hands-on activities. Light propagation through different media, image formation using lenses and mirrors under different conditions and application of basic principles to characterization of lenses, mirrors and other instruments has been a subject which although fascinates students but due to lack of suitable demonstrating setups, students find difficulty in understanding these concepts and hence unable to appreciate the importance of such concepts in various useful scientific apparatus, day to day life, instruments and devices. Therefore, students tend to cram various concepts related to geometrical optics instead of understanding them. As part of the extension activity in the University Grants Commission major research project "Investigating science hands-on to promote innovation and research at undergraduate level" and University of Delhi at Acharya Narendra Dev College SPIE student chapter, students working under this optics outreach programme have demonstrated various experiments on geometrical optics using a five beam laser ray box and various optical components like different types of mirrors, lenses, prisms, optical fibers etc. The various hands-on activities includes demonstrations on laws of reflection, image formation using plane, concave and convex mirrors, mirror formula, total internal reflection, light propagation in an optical fiber, laws of refraction, image formation using concave and convex lenses and combination of these lenses, lens formula, light propagation through prisms, dispersion in prism, defects in eye- Myopia and hypermetropia. Subjects have been evaluated through pre and post tests in order to measure the improvement in their level of understanding.
Optical sensor for the determination of adulteration in petrol: design and development
Kamal Kishor, R. K. Sinha, Anshu D. Varshney, et al.
In this paper, we report design and development of optical sensor for the determination of adulteration in petrol using optical time-domain reflectometer (OTDR). OTDR is generally used to find out fault in optical fibers but we effectively use this technique for the determination of the percentage of adulteration in petrol. This OTDR method enables detection of adulteration in petrol very accurately. The OTDR measurement method reported in this paper is easy to carry out and also a cost effective tool for the determination of adulteration in petrol.
Variation of optical polarization in reflected light by redistribution of electric charge in metals
In this work, the observation of phase delay changes between parallel and perpendicular components of an optical beam reflected on a metal surface is reported. Those changes have been induced by electrically charging a metal with static charge. A quasimonochromatic lineally polarized beam is directed to a piece of steel where the beam is reflected, the polarization of the reflected beam is in general elliptical. The module of each polarization component and their difference of phase are measured with an ellipsometer. For the experiments we have started by making ellipsometry measurements on a grounded steel sample, then a second measurement has been carried out on the same sample after inducing electrostatic charge, results indicate a rotation of the elliptical polarization in the beam reflected on the electrically charged sample.
Optical design for LED dental lighting with imaging optic technique
Young-Hoon Kwon, Seung-Chul Bae, Hae-Ryong Lim, et al.
We did a research as follows. First of all, selected optimum LEDs and mixed it for higher CRI, target CCT and illuminance. The following step is optical module design. Light directional characteristics of dental lighting must be concentrated to illuminate a part. Because This part is oral cavity, The feature of illumination pattern is rectangular. For uniformity of illuminance and clearer pattern boundary at reference distance, we designed it as direct type (no use reflector) by imaging optic technique. First, Image is rectangular feature, so object must be the same feature with magnification in general imaging optics. But the emitting surface feature of LED (1W grade) is square or circular generally. For that reason, made object as rectangular source with rectangular lightguide. This optical component was designed for higher efficiency by illumination optic technique. Next, we designed optical lenses based on imaging optic technique for image object feature using Code V. set to high NA for light efficiency in this design. Fundamentally, Finally, This product is luminaire so illumination simulation and result analysis were executed by LightTools as illumination design software.
Design and evaluation of wide field-of-view optical antenna
Peng Deng, Xiuhua Yuan, Yanan Zeng, et al.
The free space optical communication systems should utilize optical antennas with beam tracking mechanisms. However, the narrow field of view and optical aberration of antennas degrade the tracking performance of the system. In order to overcome the problems, we investigate the wide field of view optical antenna technology. The optical antenna consists of fisheye lens, compensating lens and a catadioptric telescope with off-axis aspheric surface mirrors. The structures and performances of the optical device elements are numerically analyzed so that their designs can make positive contribution in enlarging the field of view and reducing the optical aberration. The final optical antenna design is presented, along with the evaluation of optical performance and tracking characteristics. The proposed optical antenna could not only provide a wide field of view with approximately 60 degree and expand the range for tracking mechanism, but also mitigate the optical aberration and improve tracking accuracy of free space optical communication systems in turbulent atmosphere.