DIRECTED ENERGY PROFESSIONAL SOCIETY


Advanced High Power Lasers
Short Courses

24 June 2013 Santa Fe, New Mexico

These short courses were offered at the 2013 Advanced High-Power Lasers meeting, held in Santa Fe, New Mexico on 24-27 June 2013. Continuing Education Unit (CEU) credits were awarded for completion of these DEPS short courses.


    Morning Courses

  1. Ultrashort Pulse Laser Bioeffects

    Full Day Courses

  1. Introduction to High Power Semiconductor Lasers
  2. Introduction to Free Electron Lasers *
    Afternoon Courses

  1. Windows and Coatings for HEL Systems *
  2. Filamentation: Experimental Aspects


* These short courses were webcast.


Course 1.  Ultrashort Pulse Laser Bioeffects

Classification: Unclassified, Public Release

Instructors:
    - Benjamin A. Rockwell, AFRL
    - Bob Thomas, AFRL

Duration: Half-day course

CEUs awarded: 0.35

Course Description: This short course introduces the basics of the biological effects of Directed Energy on cells, tissues, organisms, and humans, with particular emphasis on the influence of such effects on the development of use of Directed-Energy-Emitting technologies. The student will learn about the mechanisms, resulting damage, and mission impact of laser-tissue interaction, as well as what tissues are most susceptible to laser damage based on wavelength, exposure duration, and irradiance. The potential mission-impact of sub-threshold, threshold, and suprathreshold exposures will be discussed. Topics include:

  • Laser damage of the eye (retina and cornea)
  • Laser damage to the skin
  • Laser safety standards
  • Laser damage as a function of energy, pulse duration, wavelength, and spot size

Intended Audience: Students need a basic knowledge of electromagnetism, such as that gained from a bachelor's program in science or engineering or on-the-job technical experience. Persons affected by laser safety standards during the development, test, evaluation, and use of Directed-Energy-Emitting equipment will find the course particularly elucidating. Individuals involved in health, science, or weapons policy will benefit from the plain language explanations of the technical subjects addressed in the course.

Instructor: Dr. Benjamin A. Rockwell is a Principal Research Physicist in the Optical Radiation Branch, Directed Energy Bioeffects Division, Human Effectiveness Directorate, of the Air Force Research Laboratory. Dr. Rockwell has co-authored 43 peer-reviewed publications, 101 proceedings publications, and published two book chapters and one review article. He is a Fellow of the Laser Institute of America. He serves on the editorial board of the Journal of Laser Applications, is the Conference Chair of the 2009 International Laser Safety Conference, and serves or has served on the national (ANSI Z136) and international (IEC TC-76) laser safety committees.


Course 2.  Introduction to High Power Semiconductor Lasers for Directed Energy Applications

Classification: Unclassified, Public Release

Instructors:
    - Paul Leisher, Rose-Holman Institute of Technology
    - Steve Patterson, DILAS USA

Duration: Full-day course

CEUs awarded: 0.70

Course Description: This short course will cover a broad range of topics related to semiconductor laser pump sources for directed energy applications. This full-day course is aimed at consumers of semiconductor lasers who wish to learn more about the technology behind these devices. A broad range of introductory topics are covered including theory, design, growth, fabrication, characterization, and packaging. Advanced topics including facet passivation technology, optical design approaches for high efficiency fiber coupling, and approaches for wavelength stabilization are also presented. Wherever possible, discussion will focus on aspects of semiconductor lasers which are most relevant to the user, such as scaling rules for quasi-CW vs. CW operation, the impact of feedback on the diode pump source (and how to avoid it), and major cost drivers. Topics include:

  • Theory of semiconductor-based light emission
  • Theory of semiconductor laser operation
  • Edge-emitting semiconductor laser design for high power, efficiency, and reliability
  • Approaches for (and challenges of) device simulation
  • Epitaxial design and growth
  • Chip design and front-end processing (wafer fabrication, cleave & coat)
  • Heatsink design and back-end processing (die and wire bonding)
  • Facet passivation technology
  • Electrical, optical, and thermal characteristics of diode lasers
  • Reliability of diode lasers - statistical approaches and accelerated lifetesting
  • Modes of operation - CW vs. QCW and scaling rules
  • Wavelength stabilization - motivation and internal vs. external approaches
  • High power fiber coupling and optical design considerations
  • Geometric, polarization, and wavelength beam combining
  • Module and system design considerations
  • Practical use in solid state and fiber laser pumping and high brightness direct diode
  • Overview of major cost drivers in development
  • Current state of the industry

Intended Audience: This course is aimed primarily at users of semiconductor laser pump sources who wish to learn more about the technology behind these devices. Much of the course will be spent addressing practical aspects (both technical and business) of diode lasers, and as such, engineers and managers alike are expected to benefit. A basic undergraduate education in science or engineering is assumed.

Instructor Biographies:Dr. Paul O. Leisher is an Associate Professor of Physics and Optical Engineering at Rose-Hulman Institute of Technology. Prior to joining Rose-Hulman in 2011, Dr. Leisher served as the Manager of Advanced Technology at nLight Corporation in Vancouver, Washington, where he worked for over four years. He received the B.S. degree in electrical engineering from Bradley University (Peoria, IL) in 2002. He received the M.S. and Ph.D. degrees in electrical and computer engineering from the University of Illinois at Urbana-Champaign in 2004 and 2007, respectively. Dr. Leisher’s research interests include the design, fabrication, characterization, and analysis of high power semiconductor lasers and other photonic devices. He has authored more than 140 technical journal articles and conference presentations. Dr. Leisher is a member of SPIE, OSA, and the IEEE Photonics Society.

Dr. Steve Patterson was appointed technical director/deputy general manager of DILAS Diode Laser, Inc. in Tucson, AZ in June 2010. Prior to joining DILAS, Dr. Patterson was the Director of Technology and Business Development at Sharp Laboratories of America. Steve served in various roles at nLight Photonics from 2004 to 2009, where he addressed the defense and commercial markets as the Director of Advanced Technologies. After nine years’ service as a United States Army Rangers, primarily with the 75th Ranger Regiment, Steve earned both Masters and Doctorate degrees from the Massachusetts Institute of Technology in electrical engineering.


Course 3.  Introduction to Free Electron Lasers (This course was Webcast)

Classification: Unclassified, Public Release

Instructors:
    - Dinh C. Nguyen, Los Alamos National Laboratory
    - Henry P. Freund, Los Alamos Nathional Laboratory

Duration: Full-day course

CEUs awarded: 0.70

Course Description: The purpose of this course is to introduce the audience to the basics of free electron lasers driven by radio-frequency linear accelerators, and to the FEL simulation and validation techniques. Basic topics to be covered include fundamental concepts of laser and electron beam physics, electron motions in an undulator, undulator radiation, FEL gain and various FEL architectures. Comprehensive discussion of FEL simulation fundamentals and applications will be discussed in both the one-dimensional and three-dimensional regimes. Examples will be given for various FEL configurations and compared with experiments to demonstrate the validity of the FEL simulations.

Intended Audience: Prerequisites for this short course include undergraduate courses in calculus and electromagnetism. Some understanding of numerical computations will be helpful.

Instructor Biographies: Dinh Nguyen received a B.S. in Chemistry from Indiana University, Bloomington in 1979 and a Ph.D. in Chemistry from the University of Wisconsin, Madison in 1984. Since joining Los Alamos National Laboratory in 1984, he has done pioneering work in laser-induced fluorescence single molecule detection, up-conversion solid-state lasers, RF photoinjectors, semiconductor photocathodes, Smith-Purcell electron bunch diagnostics, Compton backscattered x-rays and high-gain amplifier FEL concepts. One of the high-gain amplifier FEL concepts that he first demonstrated, the self-amplified spontaneous emission (SASE), is the basis of today’s x-ray FEL. His current interest includes high-power FEL, high-average-current RF injectors, advanced photocathodes and x-ray FEL. Dinh Nguyen is a member of the American Physical Society, the International FEL Conference Program Committee, and the FEL Technology Area Working Group. He has published more than 70 refereed journal articles and numerous conference papers.

Dr. Freund received a B.S. in Physics from Rensselaer Polytechnic Institute in 1971, and a Ph.D. in Physics from the University of Maryland in 1976. He is a theoretical plasma physicist currently involved in studies of coherent radiation sources such as free-electron lasers and microwave tubes by both analytical and numerical methods. He has published more than 180 papers in refereed journals, made numerous contributions to books and published proceedings, and coauthored a book entitled Principles of Free-electron Lasers [Chapman & Hall, London, 1996, 2nd edition). He is a fellow of the American Physical Society. In addition to this scholarly activity, Dr. Freund has also made contributions to more popular scientific literature with contributions on free-electron lasers published in Scientific American magazine and the Academic Press Encyclopedia of Science and Technology. Dr. Freund's work in the field of free-electron lasers includes analytic investigation of the orbital stability of relativistic electron beams in the undulator magnetic fields, the spontaneous and stimulated emission of radiation. He has developed both one- and three-dimensional nonlinear formulations of free-electron lasers, and has collaborated with experimenters at a wide range of universities, government laboratories and internationally.


Course 4.  Windows and Coatings for HEL Systems (This course was Webcast)

Classification: Unclassified, Public Release

Instructor: Bill Decker, Defense Acquisition University

Duration: Half-day course, starts at 1300

CEUs awarded: 0.35

Course Description: The student will understand the possible alternatives for Windows and Coatings for HEL Systems and sources to obtain the optical materials and coating services. Topics include:

  • Windows - issues and solutions
    • How HEL windows applications are different
    • The options for materials for tranmissive optics
    • Optical polishing technology - current state of the art
  • Coatings
    • Why coatings are still a problem
    • Sources for coating services

Intended Audience: This course will benefit those working in the high energy laser community, with a general background in optics. Technical and managerial people will benefit from the course.

Instructor Biography: William M. Decker is a Professor of Engineering Management at Defense Acquisition University. He also is a consultant to Heraeus Quartz America, a manufacturer of fused quartz and fused silica. Mr. Decker served 20 years in the U.S. Army, followed by 15 years in the optics industry prior to joining DAU. He currently serves on the DEPS Board of Directors as the Secretary. Mr. Decker's 35 years' experience in optics and lasers provides the foundation for this short course.


Course 5.  Filamentation: Experimental Aspects

Classification: Unclassified, Public Release

Instructors:
    - Howard M. Milchberg, UMD
    - John Palastro, IREAP

Duration: Half-day course, starts at 1300

CEUs awarded: 0.35

Course Description: This short course will introduce the field of intense laser-matter interactions, with specific concentration on filamentation and its applications. The tools used for both generating and diagnosing filaments will be described from an elementary perspective. Filamentation is a unique phenomenon encompassing atomic, molecular, plasma and nonlinear physics. Elements of these areas will be covered in describing filamentation itself, and the tools used to generate and diagnose them. Topics include

  • Short pulse lasers and diagnostics
  • Nonlinear wave propagation at high intensity
  • Diagnostics of filamentation

The theoretical part of this course will introduce mathematical models for ultrashort laser pulse propagation in atmosphere. A dynamic feedback between the atmospheric dielectric response and the pulse's electromagnetic field modify propagation of the pulse. The focus will be description of physical phenomena underlying the dielectric response and their affect on pulse propagation. Topics include:

  • Electromagnetic wave propagation models
    • Development of the electromagnetic wave equation from Maxwell's equations.
    • An overview of reduced propagation models including the paraxial-enveloped and uni-directional equations.
    • The physical interpretation of the approximations required for these models and the motivation thereof: computing time.
    • The best numerical approach in the absence of computing limitations.
  • Dielectric response of atmosphere
    • How the atmosphere is modified in the presence of ultrashort laser pulses.
    • Linear dielectric response: index of refraction fluctuations due to turbulence, molecular dispersion, aerosol scattering, and preformed index gradients.
    • Nonlinear dielectric response: electronic polarization, molecular alignment, and ionization.
    • Standard response models, recent improvements, and future prospects.
  • Ultrashort pulse propagation in atmosphere
    • A review of vacuum propagation concepts including phase curvature, focusing diffraction, and chirp.
    • How the linear and nonlinear dielectric response of atmosphere affects propagation.
    • Propagation in linear media: dispersion, refraction, and dispersive spreading.
    • Nonlinear propagation: self-focusing, intensity clamping, self-phase modulation, spectral broadening, temporal compression, pulse-splitting, and harmonic generation.
    • Cross-phase modulation and nonlinear birefringence due to colocalized and delayed pulses.

Instructor Biographies: Howard Milchberg received his undergraduate degree in Engineering Physics from McMaster University, in Hamilton, Ontario. He held a National Science and Engineering Research Council of Canada Fellowship at Princeton University, where he completed his Ph.D. in Astrophysical Sciences in 1985, in the plasma physics program. His dissertation was on one of the first two soft x-ray lasers experimentally demonstrated. Milchberg then joined AT&T Bell Laboratories as a postdoc, where he performed among the first experiments in high intensity femtosecond laser-plasma interactions. In 1988 Milchberg joined the University of Maryland, where he was a recipient of a NSF Presidential Young Investigator Award. He is a Professor in the Dept. of Physics and the Dept. of Electrical and Computer Engineering. Milchberg is a Distinguished Scholar-Teacher at Maryland and a Fellow of the American Physical Society and the Optical Society of America. In 2005, he was awarded the APS Division of Plasma Physics (DPP) Award for Excellence in Plasma Physics Research. Three of his graduate students, most recently in 2012, have won the APS-DPP Marshall Rosenbluth Award for their dissertation research.

Dr. John Patrick Palastro is a theoretical and computational physicist who specializes in applied electromagnetics, including nonlinear laser pulse propagation in a variety of media, plasma physics, advanced accelerators, and radiation generation. John received his B.S. degree, Summa Cum Laude, in Applied Mathematics in 2002 from Clemson University and his Ph.D. in Physics from the University of Maryland College Park in 2007. The title of his thesis was "Interaction of Lasers with Atomic Clusters and Structured Plasmas." He served as a Postdoctoral Fellow at Lawrence Livermore National Laboratory from 2007 until 2009 where he investigated nonlinear laser- plasma processes relevant to inertial confinement fusion. He then joined the Institute for Research in Electronic and Applied Physics where his primary focus has been on the propagation of high power, ultrashort lasers through atmosphere.


 
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Last updated: 25 September 2013