Download or read book Wavefront Control of High Power Laser Beams for the National Ignition Facility NIF written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of lasers as the driver for inertial confinement fusion and weapons physics experiments is based on their ability to produce high-energy short pulses in a beam with low divergence. Indeed, the focus ability of high quality laser beams far exceeds alternate technologies and is a major factor in the rationale for building high power lasers for such applications. The National Ignition Facility (NIF) is a large, 192-beam, high-power laser facility under construction at the Lawrence Livermore National Laboratory for fusion and weapons physics experiments. Its uncorrected minimum focal spot size is limited by laser system aberrations. The NIF includes a Wavefront Control System to correct these aberrations to yield a focal spot small enough for its applications. Sources of aberrations to be corrected include prompt pump-induced distortions in the laser amplifiers, previous-shot thermal distortions, beam off-axis effects, and gravity, mounting, and coating-induced optic distortions. Aberrations from gas density variations and optic manufacturing figure errors are also partially corrected. This paper provides an overview of the NIF Wavefront Control System and describes the target spot size performance improvement it affords. It describes provisions made to accommodate the NIF's high fluence (laser beam and flashlamp), large wavefront correction range, wavefront temporal bandwidth, temperature and humidity variations, cleanliness requirements, and exception handling requirements (e.g. wavefront out-of-limits conditions).
Download or read book The National Ignition Facility Wavefront Requirements and Optical Architecture written by and published by . This book was released on 2004 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the first four of its eventual 192 beams now executing shots and generating more than 100 kilojoules of laser energy at its primary wavelength of 1.06 [mu]m, the National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is already the world's largest and most energetic laser. The optical system performance requirements that are in place for NIF are derived from the goals of the missions it is designed to serve. These missions include inertial confinement fusion (ICF) research and the study of matter at extreme energy densities and pressures. These mission requirements have led to a design strategy for achieving high quality focusable energy and power from the laser and to specifications on optics that are important for an ICF laser. The design of NIF utilizes a multipass architecture with a single large amplifier type that provides high gain, high extraction efficiency and high packing density. We have taken a systems engineering approach to the practical implementation of this design that specifies the wavefront parameters of individual optics in order to achieve the desired cumulative performance of the laser beamline. This presentation provides a detailed look at the causes and effects of performance degradation in large laser systems and how NIF has been designed to overcome these effects. We will also present results of spot size performance measurements that have validated many of the early design decisions that have been incorporated in the NIF laser architecture.
Download or read book Antique Chinese Rugs written by and published by . This book was released on 1909 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Interferometric Adaptive Optics for High Power Laser Pointing Wave front Control and Phasing written by and published by . This book was released on 2009 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Implementing the capability to perform fast ignition experiments, as well as, radiography experiments on the National Ignition Facility (NIF) places stringent requirements on the control of each of the beam's pointing and overall wavefront quality. One quad of the NIF beams, 4 beam pairs, will be utilized for these experiments and hydrodynamic and particle-in-cell simulations indicate that for the fast ignition experiments, these beams will be required to deliver 50% (4.0 kJ) of their total energy (7.96 kJ) within a 40 [mu]m diameter spot at the end of a fast ignition cone target. This requirement implies a stringent pointing and overall phase conjugation error budget on the adaptive optics system used to correct these beam lines. The overall encircled energy requirement is more readily met by phasing of the beams in pairs but still requires high Strehl ratios, Sr, and rms tip/tilt errors of approximately one [mu]rad. To accomplish this task we have designed an interferometric adaptive optics system capable of beam pointing, high Strehl ratio and beam phasing with a single pixilated MEMS deformable mirror and interferometric wave-front sensor. We present the design of a testbed used to evaluate the performance of this wave-front sensor below along with simulations of its expected performance level.
Download or read book Gedenkblatt zum 19 April 1874 der Revision der Schweizerischen Bundesverfassung written by and published by . This book was released on 1874 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced High power Lasers written by Marek Osiński and published by SPIE-International Society for Optical Engineering. This book was released on 2000 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work brings together a series of papers dealing with various aspects of advanced high-power laser technology.
Download or read book Absolute Wavefront Measurements of High energy Laser Beams in the Beamlet Demonstration Project for the National Ignition Facility written by and published by . This book was released on 1994 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors measure the absolute wavefront of Beamlet output pulses and actively correct for slowly varying aberrations present when the power amplifiers are not fired. Provision is also made for active precompensation of pump-induced amplifier aberrations.
Download or read book Per Krohg Kunstforeningen 26 marts 17 april 1966 written by and published by . This book was released on 1966 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Special Section on Fusion Laser Engineering written by and published by . This book was released on 2004 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Ignition Facility (NIF) now under construction at Lawrence Livermore National Laboratory contains a large frequency-tripled neodymium glass laser system designed to deliver approximately 2 megajoules of ultraviolet laser light in nanosecond pulses to targets for the study of high-energy-density physics and inertial confinement fusion. When all 192 laser beams are operational in 2008 it will dwarf any currently operating laser system, and even with only four beams now operating it is among the largest and most energetic of such systems. This special section is a collection of papers covering important issues in the optical engineering of large lasers such as NIF. A number of other papers on NIF engineering issues can be found in the Proceedings of SPIE, volume 5341. The first paper by Miller, Moses, and Wuest is an overview of the NIF project and the applications for which the facility was designed. The following papers discuss specific issues in greater depth. Spaeth, et al., discuss the NIF laser architecture, the effect of optical performance specifications on the focal spot size, and some aspects of cleanliness in large laser systems. Bonnano discusses the strategy for assembling NIF from ''line-replaceable units'' (LRU) that are assembled in a cleanroom and transported to the laser system in sealed containers that mate with the laser enclosures and allow clean installations without maintaining cleanroom standards throughout the facility. Zacharias, et al., discuss the alignment and wavefront control systems that allow beams to strike the target within ±50 microns after a beam path of about 350 meters. Shaw, et al., discuss a laser performance operations model that is used to set up the laser for a shot, and compare the predictions of the model to data from the first four operating beams. Ermolaeva, et al. discuss the design and performance of a custom optical fiber that was developed for use in NIF ultraviolet diagnostics. Finally, Honig discusses what has been learned about cleanliness issues in large lasers from past operating systems, and how their cleanliness compares to NIF using the new assembly strategies and techniques.
Download or read book The National Ignition Facility written by and published by . This book was released on 2003 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Ignition Facility, a center for the study of high energy density plasma physics and fusion energy ignition, is currently under construction at the Lawrence Livermore National Laboratory. The heart of the NIF is a frequency tripled, flashlamp-pumped Nd:glass laser system comprised of 192 independent laser beams. The laser system is capable of generating output energies of 1.8MJ at 351nm and at peak powers of 500 TW in a flexible temporal pulse format. A description of the NIF laser system and its major components is presented. We also discuss the manufacture of nearly 7500 precision large optics required by the NIF including data on the manufactured optical quality vs. specification. In addition, we present results from an on-going program to improve the operational lifetime of optics exposed to high fluence in the 351-nm section of the laser.
Download or read book National Ignition Facility Subsystem Design Requirements Beam Control Laser Diagnostics SSDR 1 7 written by and published by . This book was released on 1996 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Subsystem Design Requirement document is a development specification that establishes the performance, design, development, and test requirements for the Alignment subsystem (WBS 1.7.1), Beam Diagnostics (WBS 1.7.2), and the Wavefront Control subsystem (WBS 1.7. 3) of the NIF Laser System (WBS 1.3). These three subsystems are collectively referred to as the Beam Control & Laser Diagnostics Subsystem. The NIF is a multi-pass, 192-beam, high-power, neodymium-glass laser that meets requirements set forth in the NIF SDR 002 (Laser System). 3 figs., 3 tabs.
Download or read book MOEMS written by M. Edward Motamedi and published by SPIE Press. This book was released on 2005 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the exciting and fast-moving field of MOEMS to graduate students, scientists, and engineers by providing a foundation of both micro-optics and MEMS that will enable them to conduct future research in the field. Born from the relatively new fields of MEMS and micro-optics, MOEMS are proving to be an attractive and low-cost solution to a range of device problems requiring high optical functionality and high optical performance. MOEMS solutions include optical devices for telecommunication, sensing, and mobile systems such as v-grooves, gratings, shutters, scanners, filters, micromirrors, switches, alignment aids, lens arrays, and hermetic wafer-scale optical packaging. An international team of leading researchers contributed to this book, and it presents examples and problems employing cutting-edge MOEM devices. It will inspire researchers to further advance the design, fabrication, and analysis of MOEM systems.
Download or read book Alignment and Diagnostics on the National Ignition Facility Laser System written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The NIF laser system will be capable of delivering 1.8MJ of 351nm energy in 192 beams. Diagnostics instruments must measure beam energy, power vs. time, wavefront quality, and beam intensity profile to characterize laser performance. Alignment and beam diagnostics are also used to set the laser up for the high power shots and to isolate problems when performance is less than expected. Alignment and beam diagnostics are multiplexed to keep the costs under control. At the front-end the beam is aligned and diagnosed in an input sensor package. The output 1053nm beam is sampled by collecting a 0.1% reflection from an output beam sampler and directing it to the output sensor package (OSP). The OSP also gets samples from final focus lens reflection and samples from the transport spatial filter pinhole plane. The output 351nm energy is measured by a calorimeter collecting the signal from an off-axis diffractive beam-sampler. Detailed information on the focused beam in the high-energy target focal plane region is gathered in the precision diagnostics. This paper describes the design of the alignment and diagnostics on the NIF laser system.
Download or read book Application of Adaptive Optics for Controlling the NIF Laser Performance and Spot Size written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Ignition Facility (NIF) laser will use a 192-beam multi-pass architecture capable of delivering several MJ of UV energy in temporal pulse formats varying from sub-ns square to 20 ns precisely-defined high-contrast shapes. Each beam wavefront will be subjected to effects of optics inhomogeneities, figuring errors, mounting distortions, prompt and slow thermal effects from flashlamps, driven and passive air-path turbulence, and gravity-driven deformations. A 39-actuator intra-cavity deformable mirror, controlled by data from a 77-lenslet Hartman sensor will be used to correct these wavefront aberrations and thus to assure that stringent farfield spot requirements are met. We have developed numerical models for the expected distortions, the operation of the adaptive optic system, and the anticipated effects on beam propagation, component damage, frequency conversion, and target-plane energy distribution. These models have been extensively validated against data from LLNL's Beamlet, and Amplab lasers. We review the expected beam wavefront aberrations and their potential for adverse effects on the laser performance, describe our model of the corrective system operation, and display our predictions for corrected-beam operation of the NI.
Download or read book Distributed Feedback Fiber Laser The Heart of the National Ignition Facility written by G. V. Erbert and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Ignition Facility (NIF) is a world-class laser fusion machine that is currently under construction at Lawrence Livermore National Laboratory (LLNL). The 192 laser beams that converge on the target at the output of the NIF laser system originate from a low power fiber laser in the Master Oscillator Room (MOR). The MOR is responsible for generating the single pulse that seeds the entire NIF laser system. This single pulse is phase-modulated to add bandwidth, and then amplified and split into 48 separate beam lines all in single-mode polarizing fiber. Before leaving the MOR, each of the 48 output beams are temporally sculpted into high contrast shapes using Arbitrary Waveform Generators. The 48 output beams of the MOR are amplified in the Preamplifier Modules (PAMs), split and amplified again to generate 192 laser beams. The 192 laser beams are frequency converted to the third harmonic and then focused at the center of a 10-meter diameter target chamber. The MOR is an all fiber-based system utilizing highly reliable Telecom-Industry type hardware. The nearly 2,000,000 joules of energy at the output of the NIF laser system starts from a single fiber oscillator that fits in the palm of your hand. This paper describes the design and performance of the laser source that provides the precision light to the National Ignition Facility. Shown below is a simplified diagram illustrating the MOR's basic functions.
Download or read book The National Ignition Facility written by C. R. Wuest and published by . This book was released on 2004 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized facility containing a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system together with a 10-meter diameter target chamber with room for nearly 100 experimental diagnostics. NIF will be the world's largest and most energetic laser experimental system, providing a scientific center to study inertial confinement fusion (ICF) and matter at extreme energy densities and pressures. NIF's energetic laser beams will compress fusion targets to conditions required for thermonuclear burn, liberating more energy than required to initiate the fusion reactions. Other NIF experiments will study physical processes at temperatures approaching 108 K and 1011 bar, conditions that exist naturally only in the interior of stars, planets and in nuclear weapons. NIF has successfully activated, commissioned, and utilized the first four beams of the laser system to conduct over 300 shots between November 2002 and August 2004. NIF laser scientists have established that the laser meets nearly all performance requirements on a per beam basis for energy, uniformity, timing, and pulse shape. Using these four beams, ICF and high-energy-density physics researchers have conducted a number of experimental campaigns resulting in high quality data that could not be reached on any other laser system. We discuss the successful NIF Early Light Program including details of laser performance, examples of experiments performed to date, and recent advances in the ICF Program that enhance prospects for successful achievement of fusion ignition on NIF.
Download or read book Laser Design Basis for the National Ignition Facility written by and published by . This book was released on 1994 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlled nuclear fusion initiated by highly intense laser beams has been the subject of experiment for many years. The National Ignition Facility (NIF) represents the culmination of design efforts to provide a laser facility that will successfully demonstrate fusion ignition in the laboratory. In this so-called inertial confinement approach, energetic driver beams (laser, X-ray, or charged particle) heat the outer surface of a spherical capsule containing deuterium and tritium (DT) fuel. As the capsule surface explosively evaporates, reaction pressure compresses the DT fuel causing the central core of the fuel to reach extreme density and temperature. When the central temperature is high enough, DT fusion reactions occur. The energy released from these reactions further heats the compressed fuel, and fusion burn propagates outward through the colder regions of the capsule much more rapidly than the inertially confined capsule can expand. The resulting fusion reactions yield many times more energy than was absorbed from the driver beams.
