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Optimal dynamic performance for high-precision actuators/stages.

Description: System dynamic performance of actuator/stage groups, such as those found in optical instrument positioning systems and other high-precision applications, is dependent upon both individual component behavior and the system configuration. Experimental modal analysis techniques were implemented to determine the six degree of freedom stiffnesses and damping for individual actuator components. These experimental data were then used in a multibody dynamic computer model to investigate the effect of stage group configuration. Running the computer model through the possible stage configurations and observing the predicted vibratory response determined the optimal stage group configuration. Configuration optimization can be performed for any group of stages, provided there is stiffness and damping data available for the constituent pieces.
Date: July 3, 2002
Creator: Preissner, C.; Lee, S.-H.; Royston, T. J. & Shu, D.
Partner: UNT Libraries Government Documents Department

Polarization selecting Optical Element using a Porro Prism Incorporating a thin film Polarizer in a single element

Description: A Porro prism and a light polarizer are combined in a single optical element termed a Hendrix Prism. The design provides retro-reflection of incoming light of a predetermined polarization in a direction anti-parallel to the direction of light incidence, while reflecting undesired light, i.e., that having a polarization orthogonal to the predetermined polarization, from the surface of the light polarizer. The undesired light is reflected in a direction that does not interfere with the intended operation of the device in which the Hendrix Prism is installed yet provides feedback to the system in which it is used.
Date: January 28, 2000
Creator: Hendrix, James lee
Partner: UNT Libraries Government Documents Department

National Ignition Facility subsystem design requirements optics assembly building (OAB) SSDR

Description: This Subsystem Design Requirement (SSDR) document establishes the performance, design, and verification requirements `for the conventional building systems and subsystems of the Optics Assembly Building (OAB). These building system requirements are associated with housing and supporting the operational flow of personnel and materials throughout the OAB for preparing and repairing optical and mechanical components used in the National Ignition Facility (NIF) Laser and Target Building (LTAB). This SSDR addresses the following subsystems associated with the OAB: * Structural systems for the building spaces and operational-support equipment and building- support equipment. * Architectural building features associated with housing the space, operational cleanliness, and functional operation of the facility. * Heating, Ventilating, and Air Conditioning (HVAC) systems for maintaining a clean and thermally stable ambient environment within the facility. * Plumbing systems that provide potable water and sanitary facilities for the occupants and stormwater drainage for transporting rainwater. * Fire Protection systems that guard against fire damage to the facility and its contents. * Material handling equipment for transferring optical assemblies and other materials within building areas and to the LTAB. * Mechanical process piping systems for liquids and gases that provide cooling, cleaning, and other service to optical and mechanical components. * Electrical power and grounding systems that provide service to the building and equipment, including lighting distribution and communications systems for the facilities. * Instrumentation and control systems that ensure the safe operation of conventional facilities systems, such as those listed above. Generic design criteria, such as siting data, seismic requirements, utility availability, and other information that contributes to the OAB design, are not addressed in this document. Rather, such information is provided in SDR 001, Conventional Facilities System Design Requirements, and SSDR 1.2.1, NIF Site Improvements Subsystem Design Requirements. Similarly, detailed requirements for building subsystems (such as specific sizes, ...
Date: August 22, 1996
Creator: Kempel, P. & Hands, J.
Partner: UNT Libraries Government Documents Department

Production and preliminary testing of multianalyte imaging sensor arrays

Description: This report covers the production and preliminary testing of fiber optic sensors that contain a discrete array of analyte specific sensors on their distal ends. The development of the chemistries associated with this technology is covered elsewhere.
Date: November 1, 1994
Creator: Richards, J.B.; Brown, S.B.; Milanovich, F.P.; Healey, B.G.; Chadha, S. & Walt, D.R.
Partner: UNT Libraries Government Documents Department

Effects of imbalance and geometric error on precision grinding machines

Description: To study balancing in grinding, a simple mechanical system was examined. It was essential to study such a well-defined system, as opposed to a large, complex system such as a machining center. The use of a compact, well-defined system enabled easy quantification of the imbalance force input, its phase angle to any geometric decentering, and good understanding of the machine mode shapes. It is important to understand a simple system such as the one I examined given that imbalance is so intimately coupled to machine dynamics. It is possible to extend the results presented here to industrial machines, although that is not part of this work. In addition to the empirical testing, a simple mechanical system to look at how mode shapes, balance, and geometric error interplay to yield spindle error motion was modelled. The results of this model will be presented along with the results from a more global grinding model. The global model, presented at ASPE in November 1996, allows one to examine the effects of changing global machine parameters like stiffness and damping. This geometrically abstract, one-dimensional model will be presented to demonstrate the usefulness of an abstract approach for first-order understanding but it will not be the main focus of this thesis. 19 refs., 36 figs., 10 tables.
Date: June 1, 1997
Creator: Bibler, J.E.
Partner: UNT Libraries Government Documents Department

Large aperture kinoform phase plates in fused silica for spatial beam smoothing on Nova and the Beamlet Lasers

Description: It is now widely recognized that spatial beam smoothing (homogenization) is essential in coupling the laser energy to the inertial confinement fusion (ICF) targets. For the indirect drive approach to ICF, it is desirable to distribute the laser energy into a uniformly speckled profile that has a flat-top super-Gaussian envelope (8th power or higher) and contains greater than 95% of the energy inside the super-Gaussian profile. Spatial smoothing is easily achieved by introducing a binary random phase plate (RPP) in the beam. This produces a homogenized far-field pattern which consists of an overall envelope function determined by the RPP element superimposed with a fine scale speckle pattern arising due to the interference among the various RPP elements. Although easy to fabricate and currently in routine use in many fusion laboratories, the binary RPPs do not meet the ICF requirements stated above since the far-field intensity profile is restricted to essentially an Airy function containing only 84% (an upper limit) of the energy inside the central spot. Approaches using lenslet arrays (refractive or diffractive) have limited use since they operate in the quasi-far-field and have a short depth of focus. The limitations of the RPPs can be overcome by relaxing the binary phase constraint. We have recently presented 5 continuously varying phase screens for tailoring the focal plane irradiance profiles. Called kinoform phase plates (KPPs), these phase screens offer complete flexibility in tailoring the focal plane envelope and, at the same time, increasing the energy efficiency inside the focal spot. In this paper we discuss the design and fabrication of such kinoform phase plates in fused silica for spatial beam smoothing on the Nova and the Beamlet lasers. Since the phase plates are used at the end of the laser chain, KPPs on Nova and Beamlet have to be fabricated on ...
Date: March 1997
Creator: Rushford, M. C.; Dixit, S. N.; Thomas, I. M.; Martin, A. M. & Perry, M. D.
Partner: UNT Libraries Government Documents Department

National Ingition Facility subsystem design requirements optics subsystems SSDR 1.6

Description: This Subsystems Design Requirement (SSDR) document specifies the functions to be performed and the subsystems design requirements for the major optical components. These optical components comprise those custom designed and fabricated for amplification and transport of the full aperture NIF beam and does not include those off-the-shelf components that may be part of other optical sub-systems (i.e. alignment or diagnostic systems). This document also describes the optical component processing requirements and the QA/damage testing necessary to ensure that the optical components meet or exceed the requirements.
Date: August 30, 1996
Creator: English, R.E.
Partner: UNT Libraries Government Documents Department

Working with the superabrasives industry to optimize tooling for grinding brittle materials

Description: The optics manufacturing industry is undertaking a significant modernization, as computer-numeric-controlled (CNC) equipment is joining or replacing open-loop equipment and hand lapping/polishing on the shop floor. Several prototype CNC lens grinding platforms employing ring tools are undergoing development and demonstration at the Center for Optics Manufacturing in Rochester, NY, and several machine tool companies have CNC product lines aimed at the optics industry. Benefits to using CNC ring tool grinding equipment include: essentially unlimited flexibility in selecting radii of curvature without special radiused tooling, the potential for CIM linkages to CAD workstations, and the cultural shift from craftsmen with undocumented procedures to CNC machine operators employing computerized routines for process control. In recent years, these developments, have inspired a number of US optics companies to invest in CNC equipment and participate in process development activities involving bound diamond tooling. This modernization process,extends beyond large optics companies that have historically embraced advanced equipment, to also include smaller optical shops where a shift to CNC equipment requires a significant company commitment. This paper addresses our efforts to optimize fine grinding wheels to support the new generation of CNC equipment. We begin with a discussion of how fine grinding fits into the optical production process, and then describe an initiative for improving the linkage between optics industry and the grinding wheel industry. For the purposes of this paper, we define fine wheels to have diamond sizes below 20 micrometers, which includes wheels used for what is sometimes called medium grinding (e.g. 10-20 micrometers diamond) and for fine grinding (e.g. 2-4 micrometers diamond).
Date: May 1, 1996
Creator: Taylor, J.S.; Piscotty, M.A.; Blaedel, K.L. & Gray, F.A.
Partner: UNT Libraries Government Documents Department

Pad polishing for rapid production of large flats

Description: Pad polishing is an efficient technique for polishing-out a ground surface and reaching a figure better than one wave, ready for completion with less than an hour on a planetary polisher. For the 350 mm square piece of BK-7, removal was one micrometer every 10 minutes. Polishing-out from a 5 micrometer grind took less than 3 hours, to a surface smoothness of one nm rms. Other tests verified that the pad leaves no unusual subsurface damage. Following completion on a pitch planetary polisher, surface finish is the same as obtained for conventional processing. Unlike pitch, the pad retains its surface figure, producing a uniform result when used on a production basis. Coupled with the speed of production and low capital cost of overarm machines, it provides a cost-effective approach.
Date: November 1, 1997
Creator: Berggren, R.R. & Schmell, R.A.
Partner: UNT Libraries Government Documents Department

Comparison of Materials for Use in the Precision Grinding of Optical Components

Description: Precision grinding of optical components is becoming an accepted practice for rapidly and deterministically fabrication optical surfaces to final or near-final surface finish and figure. In this paper, a comparison of grinding techniques and materials is performed. Flat and spherical surfaces were ground in three different substrate materials: BK7 glass, chemical vapor deposited (CVD) silicon carbide ceramic, and sapphire. Spherical surfaces were used to determine the contouring capacity of the process, and flat surfaces were used for surface finish measurements. The recently developed Precitech Optimum 2800 diamond turning and grinding platform was used to grind surfaces in 40mm diameter substrates sapphire and silicon carbide substrates and 200 mm BK7 glass substrates using diamond grinding wheels. The results of this study compare the surface finish and figure for the three materials.
Date: December 31, 1997
Creator: Evans, Boyd M. III; Miller, Arthur C. Jr. & Egert, Charles M.
Partner: UNT Libraries Government Documents Department

Documentation concerning KKP development work

Description: Fabrication has been completed on a 16 level KPP on a 5-inch diameter aperture fused silica using lithographic techniques and wet etching of fused silica in a buffered hydrofluoric acid solution. The experimentally measured far-field intensity pattern displays the desired top-hat envelope and has a superimposed speckle on it. The far-field contains 90% of the incident energy inside the 640 {mu}m region. This is a significant improvement over the binary RPP`s in terms of the far-field profile control and energy concentration. Sources contributing to the energy loss are identified and efforts are underway to overcome these limitations.
Date: December 22, 1994
Creator: Dixit, S.; Thomas, I.; Rushford, M. & Merrill, R.
Partner: UNT Libraries Government Documents Department

Characterization of surface and sub-surface defects in optical materials using the near field evanescent wave

Description: In this paper, we characterize surface and sub-surface defects in fused silica and optical coatings using the surface evanescent wave measured by NSOM implemented on a large-stage AFM. A laser irradiates the sample surface in a total internal reflection configuration. The evanescent wave from the surface is collected by an apertured fiber probe of the NSOM. The amplitude of the surface evanescent wave is proportional to the laser intensity at the surface and therefore sensitive to surface as well as sub-surface defects located in the near-field range (~ 100nm). This subsurface region is thought to contain the great majority of polishing-induced defects. The apertured near field fiber probe provides a spatial resolution of ~100nm and the large stage AFM makes it possible to locate defects in samples with diameters up to 6". We are thus able to map out surface- as well as near-surface optical defects in a large optic as a first step in understanding laser damage mechanisms. These observed defects will be exposed in situ to high fluence laser light to correlate with the initiation of laser damage. We have also used NSOM to measure in situ the effect of chemical etching on optical properties of defects. Post-processing such as chemical etching performed after mechanical polishing is frequently used, and sometimes increases laser damage thresholds. We have measured the amplitude variation of the near field evanescent wave around nodular defects and sub-surface inclusions in optical coatings and thus detected local laser field intensification. The observed intensity variation of the evanescent wave agrees with theoretical calculations of laser amplification around the inclusion. These findings support the theory that laser damage may be induced by local electrical field enhancement associated with micron and sub-micron defects.
Date: September 17, 1998
Creator: Kozlowski, M; Oberhelman, S; Siekhaus, W; Wang, L & Yan, M
Partner: UNT Libraries Government Documents Department

The National Ignition Facility (NIF) wavefront control system

Description: A wavefront control system will be employed on NIF to correct beam aberrations that otherwise would limit the minimum target focal spot size. For most applications, NIF requires a focal spot that is a few times the diffraction limit. Sources of aberrations that must be corrected include prompt pump-induced distortions in the laser slabs, thermal distortions in the laser slabs from previous shots, manufacturing figure errors in the optics, beam off-axis effects, gas density variations, and gravity, mounting, and coating- induced optic distortions. The NIF Wavefront Control System consists of five subsystems: 1) a deformable mirror, 2) a wavefront sensor, 3) a computer controller, 4) a wavefront reference system, and 5) a system of fast actuators to allow the wavefront control system to operate to within one second of the laser shot. The system includes the capability for in situ calibrations and operates in closed loop prior to the shot. Shot wavefront data is recorded. This paper describes the function, realization, and performance of each wavefront control subsystem. Subsystem performance will be characterized by computer models and by test results. The focal spot improvement in the NIF laser system effected by the wavefront control system will be characterized through computer models.
Date: August 17, 1998
Creator: Van Atta, L; Bliss, E; Bruns, D; Feldman, M; Grey, A; Henesian, M et al.
Partner: UNT Libraries Government Documents Department

Ultra-low-power, long-wavelength photoreceivers for massively-parllel optical data links

Description: An ultra-low-power, long-wavelength photoreceiver based on InGaAs/InP heterojunction bipolar transistors is reported. The photoreceivers were designed for massively parallel applications where low-power density is necessary for both electrical and thermal reasons. We demonstrate two-dimensional, four-by-four arrays of photoreceivers for free-space optical data links that interface directly with 3.3 V CMOS ASICs and dissipate less than 12 mW/channel; lower power is possible. Propagation delays of {approx}1 nsec were measured and large signal operation of 800 Mbits/sec is demonstrated. The array is on a 500 {mu}m pitch and can be easily scaled to much higher density. The photoreceivers can be utilized in both free-space and guided-wave applications.
Date: March 1, 1996
Creator: Lovejoy, M.L.; Patrizi, G.A.; Enquist, P.M.; Carson, R.F.; Craft, D.C. & Shul, R.J.
Partner: UNT Libraries Government Documents Department

Laser beaming demonstrations at the Starfire Optical Range

Description: The ability to acquire, track, and accurately direct a laser beam to a satellite is crucial for power-beaming and laser-communications. To assess the state of the art in this area, a team consisting of Air Force Phillips Laboratory, Sandia National Laboratories, and COMSAT Corporation personnel performed some laser beaming demonstrations to various satellites. A ruby laser and a frequency-doubled YAG laser were used with the Phillips Lab Starfire Optical Range (SOR) beam director for this activity. The ruby laser projected 20 J in 6 ms out the telescope with a beam divergence that increased from 1.4 to 4 times the diffraction limit during that time. The doubled YAG projected 0.09 J in 10 ns at 20 Hz. The SOR team demonstrated the ability to move rapidly to a satellite, center it in the telescope, then lock onto it with the tracker, and establish illumination. Several low-earth-orbit satellites with corner-cube retro-reflectors were illuminated at ranges from 1000 to 6000 km with a beam divergence estimated to be about 20 {mu}radians. The return signal from the ruby laser was collected in a 15-cm telescope, detected by a photomultiplier tube, and recorded at 400 kHz. Rapid variations in intensity (as short at 15 {mu}s) were noted, which may be due to speckles caused by phase interference from light reflected from different retro-reflectors on the satellite. The return light from the YAG was collected by a 35-cm telescope and detected by an intensified CCD camera. The satellite brightened by about a factor of 30 in the sunlight when the laser was turned on, and dimmed back to normal when the 50-{mu}radian point-ahead was turned off. The satellite was illuminated at 1 Hz as it entered the earth`s shadow and followed for about 10 seconds in the shadow. In another demonstration, four neighboring GEO satellites ...
Date: March 1, 1995
Creator: Lipinski, R.J.; Meister, D.C.; Tucker, S.; Leatherman, P.; Fugate, R.Q.; Maes, C. et al.
Partner: UNT Libraries Government Documents Department

System design and implementation for the glass panel alignment and sealing tool for flat panel displays

Description: This report describes the system designed and fabricated for the National Center for Advanced Information Component Manufacturing (NCAICM) project number 9322-135. The system is a device capable of simultaneously aligning two glass plates and sealing them together with glass frit. The process development was divided into two phases. The first was thermal sealing in an ambient environment. The second was sealing a controlled environment in a vacuum.
Date: October 16, 1996
Creator: Jordan, J.D.; Stromberg, P.G. & Kuszmaul, S.S.
Partner: UNT Libraries Government Documents Department

Development of a metrology instrument for mapping the crystallographic axis in large optics

Description: A metrology instrument has been developed to scan crystals and map the peak tuning angles for frequency conversion from the infrared to the ultra violet over large apertures. The need for such a device emerged from the National Ignition Facility (NIF) program where frequency conversion crystals have been found to have significant crystallographic axis wander at the large NIF aperture size of 4 1 cm square. With only limited access to a large aperture laser system capable of testing these crystals, scientists have been unable to determine which crystal life-cycle components most affect these angular anomalies. A system that can scan crystals with a small diameter probe laser beam and deliver microradian accuracy and repeatability from probe point to probe point is needed. The Crystal Alignment Verification Equipment (CAVE) is the instrument designed to meet these needs and fit into the budget and time constraints of the ongoing NIF development. In order to measure NIF crystals, the CAVE has a workspace of 50 x 50 cm and an angular measurement accuracy of 10 {micro}radians. Other precision requirements are probe beam energy measurement to 2% of peak, thermal control to 20 0. 1°C around the crystal, crystal mounting surface flatness of 1 {micro}m over 40 cm square, and clean operations to Class 100 standards. Crystals are measured in a vertical position in a kinematic mount capable of tuning the crystal to 1 {micro}radian. The mirrors steering the probe beam can be aligned to the same precision. Making tip/tilt mounts with microradian level adjustment is relatively commonplace. The real precision engineering challenge of the CAVE system is maintaining the angular alignment accuracy of the probe laser relative to the crystal for each spatial position to be measured. The design team determined that a precision XY stage with the required workspace and angular ...
Date: October 21, 1998
Creator: Hibbard, R L; Liou, L W; Michie, R B & Summers, M D
Partner: UNT Libraries Government Documents Department

Fabrication of Integrated Diffractive Micro-Optics for MEMS Applications

Description: We investigated the fabrication of integrated diffractive micro-optical features on MEMS structures for the purpose of motion detection. The process of producing the diffractive features and the MEMS structures by focused ion beam milling is described in detail, as is the ion beam sputtering process used to produce coatings on these structures. The diffractive features of the circular Fresnel zone plate (FZP) and spiral FZP were fabricated on MEMS structures and the relevant diffraction theory is discussed. The spiral FZP diffractive features produced well defined foci whose intensity varies with distance from the FZP. Observation of these intensity variations enabled us to detect the motion of the MEMS structure, and the resulting device was used to scan an IR image of a hot object.
Date: August 10, 2001
Creator: Senesac, L. R.
Partner: UNT Libraries Government Documents Department