Past Around the Lab Issues - Laboratory for Laser Energetics

Two-Plasmon–Decay Suppression Using Laser Wavelength Detuning

For direct-drive inertial confinement fusion (ICF) experiments, the two-plasmon–decay (TPD) instability poses significant problems given its low threshold and high-energy electron generation.

March 2018

Advancement of Hybrid Fluid-Kinetic Modeling Efforts for High-Energy-Density–Physics and Inertial Confinement Fusion Science

Adam Sefkow, Assistant Professor of Mechanical Engineering and Physics at the University of Rochester and senior scientist at the University's Laboratory for Laser Energetics (LLE), compares his research in high-energy-density physics (HEDP) and inertial confinement fusion (ICF) to that of a detective determined to solve an enigma. He builds on the achievements of other scientists; interprets data learned from experiments at LLE, Lawrence Livermore National Laboratory, and Sandia National Laboratories; and recognizes how often something significant can be learned from unexpected results. The recipient of both an Early Career Research Program award from the U.S. Department of Energy and the 2017 Excellence in Fusion Engineering Award from the Fusion Power Associates, Sefkow is currently developing a hybrid fluid-kinetic multiphysics simulation code named CHIMERA.

December 2017

Laser-Driven Magnetized Liner Inertial Fusion

Until recently, most of the research into nuclear fusion (which holds the promise of creating unlimited, clean power production) focused on either magnetic confinement (low plasma density) or inertial confinement (high plasma density). However, hybrid techniques, such as magneto-inertial fusion utilizing targets shown above, are gaining increased attention since their smaller size, energy, and power density requirements are proving to be cost effective.

July 2017

Commissioning an X-Ray Detector System for Spectral Analysis of Tritium-Filled Targets

LLE uses glass and plastic targets filled with deuterium–tritium mixtures (DT) for research into inertial confinement fusion experiments. The 60-beam OMEGA Laser System is employed to implode these targets. Because targets require pressurizing to tens of atmospheres without crushing the fragile, thin-wall shells, the permeation-filling process can take several days. Typically, it takes five or six permeation time constants to fill targets to the desired pressure. An x-ray detection system (XDS), originally developed to measure bremsstrahlung of tritium β decay from the surface of metals, has been modified to nondestructively measure the pressure of DT fuel inside a target just prior to a shot.

March 2017

Laser and Target Area System Developed for the Dynamic Compression Sector

The University of Rochester's Laboratory for Laser Energetics (LLE) developed a 100-J UV laser and target area system for the Dynamic Compression Sector (DCS) at the Advanced Photon Source (APS) located at the Argonne National Laboratory near Chicago. This new research facility is operated by Washington State University (WSU) under sponsorship from the National Nuclear Security Administration (NNSA). LLE partnered with Logos Technologies to develop and build the high-energy laser, which is suitable for a broad range of applications. The APS is a state-of-the-art user facility dedicated to dynamic compression science, a field that researches materials under extreme conditions.

October 2016

Computational Chemistry Modeling and Design of Photoswitchable Alignment Materials for Optically Addressable Liquid Crystal Devices

Photoalignment technology, based on optically switchable "command surfaces," has been receiving increasing interest for liquid crystal optics and photonics device applications. Azobenzene compounds in the form of low-molar-mass, water-soluble salts deposited either directly on the substrate surface or after dispersion in a polymer binder have been almost exclusively employed for these applications. Ongoing research in the area follows a largely empirical materials design and development approach. This process is time consuming, labor intensive, and wasteful of costly, and potentially scarce, materials resources because of the need to synthesize a large number of compounds to establish trends in physical properties.

Here, Emily Sekera (B.S. Chemistry, Rochester Institute of Technology 2015) and Research Chemist, Kenneth Marshall, are shown in front of a computationally generated molecular model of an azobenzene photoswitchable alignment material being investigated for use in an optically addressable liquid crystal beam shaper.

June 2016

Custom-Printed Circuit Board Development by LLE's Electronics and Controls Engineering Group

The 24 engineers and technicians who form the Electronics and Controls Engineering Group at the University of Rochester's Laboratory for Laser Energetics have procured new equipment to efficiently construct custom-printed circuit boards (PCB's). Custom PCB prototypes, which are applied to laser-fusion research, can be designed, assembled, documented, tested, and corrected in-house in just a matter of days.

Here, Senior Manufacturing Engineer Joe Romano is shown using an automated Manncorp 7722FV pick-and-place machine to assemble PCB's for the solid-state Pockels-cell driver.

October 2015

Funding Aimed at Fusion Energy Awarded to the Laboratory for Laser Energetics–Sandia National Laboratories Collaboration

The Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) has announced a two-year, $3.8 million award for Sandia National Laboratories and the University of Rochester's Laboratory for Laser Energetics to study the potential of combining two different technologies to further advance their research efforts to produce controlled fusion reactions.

August 2015

An Enduring Partnership

Research scientists at the Laboratory for Laser Energetics and physicists, chemists, and computer scientists at the State University of New York (SUNY) at Geneseo have enjoyed a dynamic and enduring partnership for close to 20 years, culminating in the formation of the Nuclear and Plasma Diagnostics Development Laboratory on the Geneseo Campus. Staffed by six faculty members and more than a dozen undergraduate students, the Laboratory engages in research projects on a part-time basis throughout the academic year and full-time during the summer months.

March 2015

The National Laser User's Facility (NLUF) turns 35!

The NLUF was born 35 years ago as a result of a workshop held at LLE to discuss the application of ultrahigh-power lasers in areas beyond fusion. The assembled panel of experts concluded that there are important applications of these systems: chemistry, biology, equation-of-state studies, effects on materials, and high-energy-density physics.

December 2014

Robert L. McCrory Appointed University Professor and Riccardo Betti Named Robert L. McCrory Professor

At an installation ceremony on 3 April, Dr. Robert L. McCrory, University Vice President and Vice Provost, and CEO and Director of the Laboratory for Laser Energetics, was appointed University Professor. Professor Riccardo Betti, professor of mechanical engineering and of physics and astronomy at the University of Rochester, was named the inaugural Robert L. McCrory Professor.

June 2014

Omega Laser Facility Reaches
its 25,000th Target Shot

The Omega Laser Facility recently completed its 25,000th experiment to create and study extreme states of matter. This achievement was noted by NNSA Deputy Administrator for Defense Programs Don Cook who underscored the important role [LLE] plays in advancing NNSA's mission of "maintaining the safety, security and effectiveness of the nuclear deterrent without nuclear testing." "It has made significant contributions to the Stockpile Stewardship Program," said Cook. "The Laboratory operates Omega as a very effective user facility. I congratulate the Omega team on this accomplishment and thank LLE for its sustained contributions to the stockpile mission."

March 2014

Implementation of a
New Neutron Temporal Diagnostic

The neutron temporal diagnostic (NTD) measures the fusion-reaction-rate history of neutrons emitted from DT- and D₂-filled targets. The neutron burn width is an important measure of confinement and is used to infer pressures exceeding 30 Gbar in cryogenic DT implosions. During June, the OMEGA NTD was replaced with a new ROSS streak-camera–based system.

September 2013

Upgrade of the MTW Laser Facility

A multi-year upgrade to the Multi-Terawatt (MTW) Laser Facility is underway that will advance high-energy-density plasma physics and ultrafast laser science at the LLE. A new ultrafast beamline, based on optical parametric chirped-pulse–amplification (OPCPA), is being added to the facility. This optical parametric amplifier line (MTW-OPAL) will generate 15-fs, 150-mJ pulses at 5 Hz synchronously with the current picosecond pulses. The upgrade also includes modifications to the MTW laser for pumping the final OPCPA amplifier to increase the energy in a single shot to 7.5 J for a peak power of 0.5 PW. This upgrade in a new 1430-sq-ft laboratory adjacent to the Laser Development Laboratory enhances current MTW research capabilities and secures the foundation for a broad range of new optical physics and ultrahigh-intensity laser research.

July 2013

Solid-State Pockels-Cell Driver Development at LLE

A vital component in the OMEGA laser, a Pockels cell is an electro-optic crystal that, when a voltage is applied to it, rotates the polarization of laser light coming through the device. Depending on the voltage employed, the Pockels cell, combined with a polarizer, can either let light pass through unabated or completely reflect light, effectively establishing an optical switch. The operation of a Pockels cell requires timed rectangular electrical pulses from a special pulse generator, or pulser, with amplitudes ranging from hundreds of volts to tens of kilovolts and pulse widths from tens to hundreds of nanoseconds.

August 2012

Using a Laser-Generated Plasma to Stimulate the Field of Nuclear Physics

The University of Rochester's Laboratory for Laser Energetics (LLE) ushered in a new frontier of plasma nuclear science at the Omega Laser Facility by measuring a nuclear scattering cross section more precisely than ever determined before with particle accelerators. "This is the first time a high-energy-density laser facility has been used to advance the field of nuclear physics," said Dr. David Meyerhofer, LLE Deputy Director and Professor of Mechanical Engineering and Physics & Astronomy. A research team from the Massachusetts Institute of Technology, Lawrence Livermore National Laboratory (LLNL), and the University of Rochester worked on the project and published their findings in the 16 September 2011 Physical Review Letters.

February 2012

Control Room Operations at LLE

The word "shot" can suggest an informal attempt, a try, or something upon which to bet. That casual attitude is far removed from the control, coordination, and caution built into all aspects of OMEGA and OMEGA EP shot operations. The atmosphere surrounding Control Room operations at LLE before a laser shot is fired feels measured, quietly assured, and cautiously anticipatory. Highly trained experienced scientists, engineers, and technicians "stand watch" at computer workstations to ensure operations move forward safely and as planned.

Above, visitors to LLE can observe operations through the Control Room window.

November 2011

The Multi-Terawatt Laser at LLE

The Multi-Terawatt laser (MTW) is a significant research tool supporting the University of Rochester's commitment to advancing research in the physics of x-ray and high-energy, directed-particle beams and ultrafast laser science at the Laboratory for Laser Energetics.

September 2011

Target Fabrication at LLE

One of the primary goals of the Laboratory for Laser Energetics is conducting implosion experiments in support of the National Inertial Confinement Fusion program. The production of these targets is a complex, delicate process carried out by LLE's Target Fabrication Group.

Above, well-controlled volumes of oil and water are dispensed electronically from a large reservoir. These droplets are electronically moved around a wafer and combined to form oil-water emulsions that are precursors for foam targets.

May 2011

Multilayer Dielectric Gratings
for OMEGA EP

High-energy, petawatt (HEPW)-class lasers depend upon the superlative performance, efficiency, and damage threshold for picosecond pulses that multilayer dielectric diffraction gratings offer for pulse compression. The Laboratory for Laser Energetics has played a major role in the worldwide effort to realize the potential of these multilayer dielectric gratings.
The installation of the new PGL gratings into the Grating Compressor Chamber is shown above.

January 2011

TIMELINE – Explore LLE’s History

Laser Lab Turns 40!

This year, the University of Rochester's Laboratory for Laser Energetics (LLE) marks its 40th anniversary as a unique national resource for investigating the interaction of intense radiation with matter. This important marker offers an opportunity to examine the highlights of the history of the LLE in order to prepare for the quest to harness nuclear fusion for the greater good.

October 2010

LLE–CEA: Ten Years of French–American Collaboration at the Omega Laser Facility

Since the first shot on Omega over a decade ago, more than 500 successful joint laser shots have been performed, thanks to the use of resources specific to CEA (targets, diagnostics, and principal investigators) and LLE teams. The CEA Experimental Program at LLE has extended the topics started on Nova, such as laser-plasma interaction, x-ray conversion, implosion symmetry and hydrodynamic instabilities.

September 2010

LLE Provides DT Fueling of
Diagnostic Commissioning Targets
for the National Ignition Campaign

During the fall of 2009 and into the spring of 2010, LLE successfully developed and tested a technique to fill room-temperature, glass targets with deuterium–tritium (DT) fuel to 10 atm as is required for diagnostic purposes on the National Ignition Facility. Above, operators mount targets in the Hoppe Target Mounting Station.

June 2010

LLE's Mechanical Engineering Group

The Mechanical Engineering Group provides a full range of mechanical design, engineering, fabrication, assembly, and testing capabilities. They specialize in designing, fabricating, and constructing unique and precise components and structures and are staffed by 26 full-time employees and 5 students. Shown above are the inner and intermediate shrouds for the new moving cryostat developed by the Mechanical Engineering group.

November 2009

New (Cd,Mn)Te X-Ray Detectors for the OMEGA Laser System

Standard x-ray detectors used on the OMEGA Laser System have typically been diamond photoconductive detectors (PCD's) and x-ray diodes (XRD's). Recently, (Cd,Mn)Te (CMT) has been closely studied as a viable material for radiation detection because it can be used for x-ray energies of up to 100 keV and is relatively easy to grow as large, high-quality (homogeneous) single crystals.

July 2009

The OMEGA Magnetic Recoil Spectrometer

The Magnetic Recoil Spectrometer (MRS), a novel neutron spectrometer under development since 2001, was installed on OMEGA in late 2008 to assess implosion performance. In collaboration with the Massachusetts Institute of Technology Plasma Science and Fusion Center, the MRS provides absolute measurements of the neutron spectrum in the range 5 to 30 MeV, from which fuel areal density, ion temperature, and neutron yield can be determined.

April 2009

The Publications and Design Department at LLE

Preparing numerous conference presentations, operations manuals, monthly Department of Energy reports, and formatting all publications that are submitted from the lab, the Publications and Design Department has earned the reputation of providing a high level of precision and an attention to detail, all with a quick turnaround.

February 2009

Contamination-Resistant Sol-Gel Technology

What started in 2004 as a Summer High School Program research project focusing on the development ofcontaminant-resistant sol-gel coatings for laser optics, has now evolved into a significant piece of technology that has been installedon the 30-TW, 60-beam OMEGA laser at the University of Rochester's Laboratory for Laser Energetics (LLE).

November 2008

2008 Summer High School Research Program

This summer, 15 Rochester-area high school students participated in the LLE Summer High School Research Program. Since 1989, this program has challenged 233 talented and dedicated high school students interested in science, mathematics, and technology to explore research topics and careers under the tutelage of LLE scientists, engineers, and staff in a state-of-the art environment. These research projects draw on the theoretical and laboratory expertise of many disciplines, including physics, optics, chemistry, spectroscopy, diagnostic development, controls engineering, software development, and materials science.

September 2008

New Target Viewing System (TVS2) Installed

A new Target Viewing System, a project under development at the University of Rochester's Laboratory for Laser Energetics since 2003, has been recently installed on the OMEGA target chamber. This system is a major redesign and upgrade of the existing TVS system.

July 2008

OMEGA EP Laser Dedication

On Friday, 16 May 2008, Dr. Robert McCrory, Vice Provost, Director, and CEO of the Laboratory for Laser Energetics (LLE), along with special guests, which included University of Rochester President Joel Seligman, U.S. Senator Charles Schumer, U.S. Congressman Thomas Reynolds, and Undersecretary for Nuclear Security for the U.S. Department of Energy Thomas D'Agostino, dedicated the new OMEGA EP laser at the Robert L. Sproull Center for Ultra High Intensity Laser Research at the Laboratory for Laser Energetics.

May 2008

Performance and Capabilities of the Cryogenic Fill-Tube Target Test Facility (CFTF) at the LLE

A small group of scientists at the Laboratory for Laser Energetics (LLE), who support research at LLE and are devoted to the priorities of the National Ignition Facility (NIF), are currently designing and building a test station to characterize advanced cryogenic targets using deuterium–tritium (DT) fuel. Future direct-drive experiments on the NIF will require that capsules be fueled using fill tubes and be supported along a horizontal orientation. Scientists at LLE are investigating the effect of the fill tube and support structure on fuel-layer uniformity.

March 2008

Magneto-Inertial Fusion: Enlisting Magnetic Fields for Improved Laser-Fusion Implosions

While most of the research at Laboratory for Laser Energetics is devoted to the priorities of the National Ignition Campaign and future direct-drive experiments on the NIF, a small group of scientists at LLE has been looking (since 2006) at alternative, potentially more productive ways to achieve ignition and burn of laser-fusion capsules. One of these alternative concepts involves the use of strong magnetic fields, something normally associated with tokamaks and other devices for magnetic-fusion (MF) research.

August 2007

The Laboratory for Laser Energetics Completes Two National Ignition Campaign Level-2 Milestones

LLE infers 200 mg/cm² fuel areal density in a cryogenic direct-drive implosion on OMEGA and LLE validates polar-direct-drive concept for ignition on the NIF.

June 2007

LLE High School Program Participants Honored

Three participants in LLE's 2006 Summer Research Program, Rui Wang from Fairport High School, Alexandra Cok from Allendale Columbia School, and Zuzana Culakova from Brighton High School, were honored in 2007 by the Intel Science Talent Search. First created in 1942 by the Westinghouse Corporation and assumed by the Intel Corporation in 1998, the Science Talent Search is often referred to as the "Junior Nobel Prize" and is the country's most prestigious science scholarship competition. Alumni of the competition include National Medal of Science winners, MacArthur Foundation fellows, Field medalists and Nobel Laureates.

April 2007

2006 Year in Review

2006 was a year of significant accomplishments at the Laboratory for Laser Energetics. Here are some of our major achievements and milestones in the past year.

January 2007

LLE Builds New High Voltage, Large Aperture Pockels Cell Drivers

To meet the demands of its OMEGA EP laser, the Laboratory for Laser Energetics added four solid-state high voltage, large-aperture Pockels-cell drivers in 2006.

December 2006

LLE Achieves Cryogenic Target Milestone

In July 2006, scientists at the University of Rochester's Laboratory for Laser Energetics achieved a major breakthrough in laser-fusion research that could have a significant impact on future energy production.

October 2006

The ROSS Streak Camera

What measurement needs are common to the search for fusion energy, molecular imaging, and the development of high-speed fiber-optic communications? The measurement of ultrafast transient events is one such common need of these and many other state-of-the-art technologies.

June 2006

Kids at Work Day 2006

On April 27, sixty-one students took a break from school to get another kind of education. The students, all children of Laboratory for Laser Energetics employees and between 8 and 14 years of age, came to the Lab for the fifth annual Kids@Work Day.

April 2006

Robert L. Sproull Center Dedicated

On 11 May 2005, LLE dedicated the Robert L. Sproull Center for Ultra High Intensity Laser Research. This facility was named in honor of the University of Rochester's seventh president and will house the OMEGA EP Laser System.

May 2005

April 28 2005: Kids at Work Day

Photos from the April 28 2005: Kids at Work Day.

April 2005

More Than a Summer Job

Participants in our Summer High School Research Program perform real research, not just summer projects. Furthermore, their work sometimes continues and impacts the Laboratory long after they have returned to their studies. Research projects performed by Bruce Brewington and Daniel Balonek are prime examples of ongoing research that stemmed from a short summer program.

April 2005

Kids at Work Day

In honor of the back-to-school season, LLE is looking back on last spring's Kids at Work Day. After and introduction to the Laboratory, this year's participants enjoyed a tour of the OMEGA EP construction site (including hard hats), facility tours, and demonstrations in target fabrication and optics. Enjoy the show!

September 2004

Cryogenic Target Characterization

The ultimate goal of inertial confinement fusion is to produce more thermonuclear energy from a laser implosion than the energy required to power the laser. Such a positive gain is a potential source of energy that can be converted to electricity. To reach this goal, laser fusion experiments must use high quality cryogenic targets. The bulk of the research performed at LLE is directed towards understanding the basic physics issues involved in these experiments and includes fabrication and characterization of cryogenic targets.

March 2004

Summer High School Program

Each February, LLE invites area high school juniors to apply to our summer research program. Selected applicants are teamed with staff advisors and spend eight weeks working on individual research projects. These projects culminate in a symposium where the students present their research findings to family, teachers, and members of the Laboratory's scientific and technical staff. Fifteen students participated in 2003–this is the second year LLE has hosted a group this large.

February 2004

Tiled Gratings

Tiled-Grating Pulse Compressor: An important element of the new OMEGA EP (extended performance) laser system is the grating compressor used to form short pulses of light at the output of the system. The most-promising technology is a holographically formed, etched grating that, combined with a multilayer dielectric (MLD) coating, forms a highly efficient grating used in reflection.

October 2003

OMEGA EP Amplifier

Amplifiers and their associated power conditioning units are the basic building blocks of any laser system. The energy required to perform ICF experiments is much greater than that in the initial beam. Amplifiers placed throughout the system incrementally increase the energy of each beam until it meets the requirements for experimental use.

June 2003

Kids @ Work Day

On April 24, 2003, LLE sponsored a morning-long program entitled Kids@Work for the national "Bring Your Children to Work Day." Forty-one children, ages 8 to 15, were treated to demonstrations, tours of laboratory facilities, and, of course, pizza! Dr. Robert McCrory, Director of LLE, opened the program by welcoming the children and describing some of the important work performed at LLE. He emphasized that LLE plays a critical role in national security and has a long-term mission based on the development of fusion energy.

May 2003

Phoebe Rounds

Recently, Phoebe Robeson Rounds was selected as a finalist in the Intel Science Talent Search for research she performed while participating in LLE's 2002 Summer High School Research Program. Phoebe developed a systematic method for generating new tripler designs for use on OMEGA or any other high-power ICF laser system. Her method involves the optimization of thickness, tilt, and spacing of the frequency-conversion crystals. Phoebe is the second student from the LLE program to advance to the finals in this nationwide competition.

April 2003

OMEGA EP Project

LLE is launching a multi-year project to build a new ultra-high power laser to complement the ongoing mission of experiments conducted on the OMEGA laser. The new project–OMEGA EP (extended performance)–is a modern architecture 4 beam laser with special capabilities in short-pulse performance (2.6 kJ in a 1-ps pulse).

March 2003

Summer High School Program

Each year, LLE invites area high school juniors to apply to a summer research program. Selected applicants are teamed with staff advisors and spend eight weeks working on individual research projects. These projects culminate in a symposium where the students present their findings to family, teachers, and members of the Laboratory's scientific and technical staff. Fifteen students participated in 2002, the largest group in the program's fourteen-year history.

February 2003

2002 Year in Review

In a September OMEGA experiment, the fusion neutron yield from a D₂-filled cryogenic target implosion was near 100% of the 1-D LILAC hydrodynamic code prediction. The time-integrated x-ray images shown above were used to assess the implosion symmetry and placement precision of the cryogenic targets. This is only one of many accomplishments that took place at LLE in 2002.

January 2003

Liquid Crystals

Liquid crystal optics have provided LLE with substantial cost and performance advantages over the years. Their unique molecular ordering gives rise to characteristic and colorful textures of great beauty when they are observed under a polarizing optical microscope.

December 2002

Planar Cryo Target Positioner

A planar cryogenic target assembly is shown above (in color) at the target filling station where vacuum testing, purging, and filling are completed. This is part of the new planar cryogenic target positioner that has been deployed on OMEGA to measure the properties of condensed gasses at cryogenic temperatures.

November 2002

Deformable Mirror Assembly

LLE's Optical Manufacturing Group is currently coating, assembling, and acceptance testing 186 deformable mirrors for use on the National Ignition Facility at Lawrence Livermore National Laboratory. LLE has optimized a low-stress, high-reflectance coating process for the deformable mirror faceplate and has developed an aluminum sputtering capability to coat the posts on the rear side of the optic.

September 2002

COM Summer School

The Center for Optics Manufacturing (COM) hosted their annual Summer School program, New Machines, Tools, and Processes for Modern Optics Manufacturing, during June 2002. This program provided an intensive overview of the emerging technologies that will shape optics manufacturing during this century.

August 2002

Moving the MCTC

The Moving Cryogenic Target Cart (MCTC) is part of the Cryogenic Target Handling System (CTHS), an operation unique to LLE. LLE is the first laboratory worldwide to create a cryogenic target with a smooth surface, transport it to the OMEGA Target Chamber while maintaining a constant temperature and vacuum, and implode the target using inertial confinement fusion. The MCTC is crucial to this process.

June 2002