This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344

Status of the E23 Project: A High Average Power Femto-Petawatt Laser for High Intensity Applications

Presentation toInternational Conference on Ultrahigh Intensity Lasers (ICUIL)

October 27-31, Shanghai-Tongli, China

Andy BayramianPhoton Science and Applications,NIF & Photon Science Directorate,

Lawrence Livermore National LaboratoryLivermore, CA

October 30, 2008

LLNL-PRES-408165

1021

NIF-1008-15525.ppt 3

Worldwide high irradiance facilities show a trend toward higher repetition rate and higher intensity

We will use our 10 Hz feedback to create focused irradiance up to 1023 W/cm2

Irradiance (W/cm2)

Rep

etiti

on R

ate

(Hz)

LLNL PW

Hercules

LULI

LOA

LLNL High Average Power Petawatt: E23

AstraGemini

SanDiego

Texas PW

Vulcan

PICO 2000

Falcon

1000

100

10

1

0.1

0.01

0.001

0.0001

ThermalManagement

Energy or Beam Quality

Nova X-ray

E16 E17 E18 E19 E20 E21 E22 E23 E24 E25

NIF0.00001

Sampling of facility capabilities around the world

JAERI

45Beam quality (xDL)In Progress>150Bandwidth (GHz)

0.520.52Frequency conversion10-203-15Pulse length (ns)

1010PRF (Hz)6.510Efficiency (%)65100Energy (J) (@ 1ω)

StatusGoals

NIF-1008-15525.ppt 5

Mercury has operated above 50 Joules for over 0.3 million shots at 10 shots per second

Mercury shot histogram of consecutive 0.5 - 2 hr operations

0 .0 0 0 .0 5 0 .1 0 0 .1 5 0 .2 0 0 .2 5 0 .3 01

1 0

1 0 0

1ω

Out

put E

nerg

y (J

)

Number of Shots (x 106)

Output Nearfield

NIF-1008-15525.ppt 6

The advanced technologies on Mercury can be applied to power scaling of Ti:sapphire systems

• Image relayed, angular multiplexed architecture• High speed helium gas cooling (scalable aperture)• MRF correction of wavefront• High average power edge cladding• Adaptive optics

100-kW Diode Arrays

Yb:S-FAP Gain

Media

High-Speed Helium Gas

Cooling

Broadband Front End With Spectral And

Temporal Sculpting

YCOB High Average Power

Frequency Conversion

Thermal Birefringence Compensated Pockels Cell

Bi-morph Adaptive Optic And Close

Loop Control

Thin Fresnel Final Optic

(TBD)

Chamber (TBD)

0.00 0.05 0.10 0.15 0.200

20

40

60

80

100

Con

vers

ion

Effic

ienc

y (%

)

Pump Intensity (GW/cm2)

Plane Wave Model

73% conversion efficiency

Conversion up to 317 W average power (31.7 J/shot) at 523 nm achieved

The Mercury diode-pumped

solid-state laser

Mercury pumped 10 Hz Ti:sapphire

petawatt

Compressor, E23, and particle generation

This high average power femto-petawatt has two distinct goals: focused irradiance and repetition rate

We will use Mercury to pump a 10 Hz petawatt

NIF-1008-15525.ppt 9

15 J Petawatt capability requires 90 Joule 1w output of the Mercury pump-laser

Expected energy on target is 15.2 J + 3.6 J / - 5.8 J (rms uncertainties)

1009080Mercury 1ω output

96.286.476.10.980.960.921ω transport

71.560.549.30.80.70.6Harmonic Conversion

66.556.244.70.950.930.852ω Transport

61.952.341.60.940.930.92Absorbed Pump Energy

34.728.819.00.60.550.4Energy Storage

27.923.015.00.850.80.75Energy Extraction

26.722.014.40.970.960.95Chirped Pulse Transport

19.415.79.70.780.710.6Compressor

18.815.29.40.980.970.95Parabolic reflector

High value

Mid valueLow

valueHigh value

Mid valueLow value

Energy (J)Efficiency

Loss Factor

NIF-1008-15525.ppt 10

10 Hz operation enables real time feedback for dispersive and spatial control of petawatt pulses

Feedback beam quality, Φ(x,y) correction

Feedback pulseshape, Φ(ω) correction

Oscillator Multipass Pre-Amplifier

4-pass Power

Amplifier

Ultrawideband Regenerative

AmplifierStretcher

Compressor

Target Chamber

Mercury 2ωBeam

Conditioning

DazzlerΦ(ω)

Deformable MirrorΦ(x,y)

Mercury 1ω

Roof mirrorRoof mirror

Cylindrical concave mirrorsCylindrical concave mirrors

Grating #2Grating #2

Grating #1Grating #1

Pulse slicerPulse slicer

Dispersion CompensatorGrating 1&2

Dispersion CompensatorGrating 1&2

Interferometric AutocorrelatorInterferometric Autocorrelator

DazzlerDazzler

OscillatorOscillator

Convexmirror

Convexmirror

StaircaseStaircase

NIF-1008-15525.ppt 12

0.0

0.2

0.4

0.6

0.8

1.0

1.2

-0.03 -0.02 -0.01 0.00 0.01 0.02 0.03

Time (ps)

Pow

er (a

u)

An end to end energetics model indicates we will maintain sufficient bandwidth to compress to 13 fs

Spectral phase correction will be accomplished using a combination of the dispersion compensator, static correctors and a Dazzler

Predicted transform-limited pulsewidth

∆t = 13.2 fs

0.0

0.2

0.4

0.6

0.8

1.0

1.2

650 700 750 800 850 900 950

Wavelength (nm)

Spec

tral

inte

nsity

(au)

E23 predicted output spectrum

∆λ = 120 nm

NIF-1008-15525.ppt 13

Our adaptive optics system will correct the low order wavefront aberration

Magneto Rheological Finishing (MRF) or deterministic polishing will be used to correct for high order abberations in the Ti:sapphire and integrated system

• Peak to valley, 2.14 waves• RMS, 0.36 waves• Ti:sapphire static MRF

corrected• Thermal wavefront 11 waves of

power, cavity corrected

Induced static wavefront due to the power amplifier

Actuator Configuration

• Large single actuator corrects power (20 waves)

• 30 small actuators (5 waves stroke)

Bi-Morph Deformable Mirror

• Paired with 10 Hz Phasics wavefront sensor

• Tested in Mercury

NIF-1008-15525.ppt 14

An off axis parabola with a NA = 0.7 (F# ~ 0.5) could focus the output to nearly 4 x 1023 W/cm2

• The optic is manufacturable using conventional techniques

• The surface deviation from a sphere is < 15 mm

4E+23

3e+23

2e+23

1e+23

0Irrad

ianc

e (W

/cm

2 )

Focal plane coordinate (µm)

-1.0 -0.5 0.0 0.5 1.0

MeridionalSagittal

5

0

-5

-10

-15

Dev

iatio

n fr

om S

pher

e (m

m)

Aperture coordinate (mm)

-150 -100 -50 0 50 100 150

Ray trace model of parabola

NIF-1008-15525.ppt 15

The thermal model for the gas-cooled amplifier in the Mercury laser has been benchmarked

The benchmarked model enables predictive capability for advanced designs

7 amplifierslabs

Helium

Pump

Pump

Mach 0.1 helium gas cooling

1.0 λ

0.5

0

Amplifier Thermal Wavefront

Model Data

NIF-1008-15525.ppt 16

Vacuum chamber surrounding amplifier head

Gas-cooled amplifier head design based on Mercury

Relay imaging used to minimize wavefront

distortions and amplitude modulation

The helium gas-cooled Ti:Sapphire amplifier head is embedded in a 4-pass image-relay cavity

The scalable average power and high beam quality capabilities of this design are new contributions to the field

NIF-1008-15525.ppt 17

The thermally induced wavefront distortion in the Ti:sapphire will be almost entirely power (focus)

Power correction can be achieved by adjusting the beam transport optics or the deformable mirror

Thermally induced wavefront distortion of the Ti:sapphire

Convectively cooled face

Vane

Pumped Sapphire region

Un-pumped sapphire region

Edge cladding

337

330

320

310

300

Temperature, oK

Half geometry showing the temperature distribution for 70 J pump energy

510 X 600 mm Gratings

510 X 600 mm Gratings

300 X 380 mmRoof mirrors

300 X 380 mmRoof mirrors

Compressor gratingin 3-axis mount

Compressor gratingin 3-axis mount

The gold gratings are fabricated with a new gold-on-glass technique with ULE substrates to limit thermal effects in the compressor

Clean EntranceClean Entrance

Class 100 enclosures Class 100

enclosures

Installation of regenerative amplifierInstallation of regenerative amplifier

Oscillator & StretcherOscillator & Stretcher

532 nm pump lasers532 nm pump lasers

Beam transport from MercuryBeam transport from Mercury

10 fs oscillator and pump lasers installed, stretcher aligned, regenerative amplifier in process

NIF-1008-15525.ppt 20

The 10 Hz Femto-Petawatt Laser will access a new high-field physics regime

The laser will provide 150 W (36000 PW shots/hr) which can generate a flux of X-rays, electrons, protons, and neutrons for high intensity applications

3 ω

3 ωE23 1ω

Petawatt / Mercury Team:Kathy AllenFelicie AlbertKathy AlvisoPaul ArmstrongChris BartyAndy BayramianGlenn BeerJohn CairdRob CampbellManny CarrilloDiana ChenRick CrossChris EbbersAl ErlandsonBarry FreitasGlenn HueteRod LanningBill MolanderNoel PetersonKathleen SchaffersNick SchenkelCraig SidersSteve SuttonJohn TassanoPeter ThelinSteve TelfordEverett Utterback

Industrial Collaborators:Blue Ridge OpticsCoherent, Inc.Crystal Systems Inc.Directed Energy, Inc.Laboratory for Laser EnergeticsNorthrop-GrummanOnyx OpticsPrecision PhotonicsPHASICSNight N (opt) Ltd.Crystal PhotonicsQuality Thin FilmsSchott Glass TechnologiesSpicaZygo

NIF Collaborators:John AdamsRay BeachErlan BlissGina BonannoJack CampbellJohn CraneSham DixitSteve FulkersonChris GatesChris HaynemMark HenesianKen JancaitisMike JohnsonLaura KegelmeyerJanice LawsonScott LernerKen ManesJoe MenapaceNaresh MehtaSteve MillsJohn MurrayJim MurrayCharles OrthChuck PettyShahida RanaGreg RogowskiRick SacksLynn SeppalaRalph SpeckChris StolzTayab SuratwalaJohn TrenholmeGary UlleryRon WhiteClay Widmayer

NIF-0000-12345.ppt 22