Technology Development and Prospects for Exawatt-Class

J. D. ZuegelUniversity of RochesterLaboratory for Laser Energetics

IZEST MeetingLivermore, CA

17–18 July 2013

Technology Development and Prospects forExawatt-Class OPCPA Pumped by OMEGA EP

DKDP

10 J, 1.5 ns, 160 nm

200 PW 1024 W/cm2

OMEGA EPtarget chamber

KDPType II Polarizer


Existing OMEGA EP will be usedto pump OMEGA EP–OPAL

Beamline 2

Beamline 3

Beamline 4

Beamline 1

Compressor

3 kJ, 15 fs

Ultra-broadbandfront end

E22248

Summary

Ultra-intense laser development at LLE is aimed atscaling technologies for an exawatt-class facility

• TheLaboratoryforLaserEnergetics(LLE) operates the Omega Laser Facility to provide high-energy kilojoule (kJ), nanosecond, and picosecond laser pulses for a wide range

of user experiments

– prototype systems, used to demonstrate key technologies, also provide a platform for ongoing research and development

• Ultra-broadbandopticalparametricamplification(OPA) pumped by kilojoule-class lasers offers a promising approach to achieve focal intensities up to 1024 W/cm2

– scalable technologies are being developed in an OPA line (OPAL) pumped by the Multi-Terawatt laser (MTW-OPAL)

An exawatt-class upgrade to OMEGA EP is a long-term goal.

Many people have contributed to this effort

Laser development andoptical engineering:

J. BromageS.-W. Bahk

I. A. BegishevJ. Bunkenburg

T. ConleyC. Dorrer

D. H. FroulaH. Huang

R. K. JungquistC. Kellogg

T. J. KesslerE. Kowaluk

J. R. MarcianteM. MillecchiaS. F. B. MorseA. V. OkishevJ. B. OliverT. Petersen

J. Qiao

Ultrafast physics:

C. StoecklD. Haberberger

P. M. NilsonG. FikselJ. F. Myatt

D. D. Meyerhofer

Outline

E22249

• Introductionandmotivation

• MTWlaser-pumpedopticalparametricamplifierline(MTW-OPAL)

– high-contrast, ultra-broadband front end (UFE)

– scalableopticalparametricchipped-pulse–amplification(OPCPA) technology development

– new MTW-OPAL laboratory

• OMEGAEP-pumpedopticalparametricamplifierline(EP-OPAL)

– technological challenges

– LLE program outline

E22249c

Outline









OMEGA Laser BayMainamplifiers

Boosteramplifiers

Beam 1 2 3 4

OMEGA Laser BayMainamplifiers

OMEGA EP Laser Bay

Compressionchamber

OMEGA EPtargetchamber

Boosteramplifiers

Beam 1 2 3 4

OMEGA targetchamber

LLE operates the Omega Laser Facility to provide high-energy (kilojoule), nanosecond and picosecond laser pulses for a wide range of user experiments

OMEGA EP Laser System• Constructioncomplete25April2008• AddsfourNIF-likebeamlines;

6.5-kJUV/beam (10 ns)• Twobeamscanbehigh-energypetawatt – 2.6-kJ IR in 10 ps – can propagate to the OMEGA or

OMEGA EP target chamber

OMEGA Laser System• OperatingatLLEsince1995• Upto1500shots/year• Fullyinstrumented• 60beams• >30-kJ UV on target• 1%to2%irradiationnonuniformity• Flexiblepulseshaping• Shortshotcycle(1 h)

• TheOmegaLaserFacilityhasbeen operating under an NNSA-approved Governance Plan for morethanfiveyears

• TheOmegaLaserUsers’Group(est. 2008) has more than 300 members

• MorethanhalfofOMEGA’sshotsare for external users

E17097w

The Multi-Terawatt (MTW) Laser System was developed to prototype many of the laser technologies used on OMEGA EP

E21876a

• TheMTWlaserisahybridOPCPAandNd:glasssystemoperatingfrom <1 ps to ~100 ps (1054nm)

• TheMTWlaserwasrecentlyupgradedto100J

• MTWisauniversity-scalefacilityoperatedforgraduateresearch,diagnostic development, and laser science

The 30-min MTW shot rate is excellent for OMEGA EP diagnostic development and graduate student research.

Hybrid OPCPA–Nd:glass laser

Oscillatorand

stretcherMTW target

chamber

Vacuumgrating

compressor

Nd:glassamplifiersMTW OPCPAUOPA*

SHG**Narrowband1053-nm pump laser

*Ultrafastopticalparametricamplifier**Second-harmonic generation

Focal intensities up to 1024 W/cm2 are possible with an OPAL pumped by OMEGA EP

E20382b

DKDP, 40 × 370 mm, square

DKDP, 14 × 370 mm, square

10 J, 1.5 ns, 160 nm 6 kJ 1.5 ns

2.5 kJ

200 PW 1024 W/cm2

OMEGA EPtarget chamber

60%, 1.4-m × 1.4-m beam300 mJ/cm2


5.0 kJ

4 kJ 1.5 ns

6 kJ

12 kJSHG

1.5 ns


An existing OMEGA EP beamline willbe used to pump OMEGA EP–OPAL

Beamline 2

Beamline 3

Beamline 4

Beamline 1

Compressor

3 kJ, 15 fs

Ultra-broadbandfront end

Outline

E22249a









AnopticalparametricamplifierlinepumpedbytheMTWlaser system (MTW-OPAL) is being developed

E21877a

MTW-OPAL will be used to develop scalable technologies for ultra-intense OPCPA while integrating new capabilities for ultrafast research.

Futuretarget area

7.5 J, 15 fs1022 W/cm2

UFE

810 to 1010 nm1.5 ns (stretched)

60J

100J

NOPA4 NOPA5

Compressorchamber

Bypass for 5-Hz operations150 mJ, 15 fs, 1020 W/cm2

Oscillatorand

stretcherMTW

target area

Vacuumgrating

compressor

Nd:glassamplifiersMTW OPCPAUOPA

60 J,1psSHG

SHGNarrowband1053-nm pump laser

The100JofMTWwillbeusedtopumpa7.5-J,15-fsMTW-OPAL

*Noncollinearopticalparametricamplifier

2

–2

0

NOPA1 spectrum and phase**

NOPA1 pulse afterprism compressor

Sp

ectr

al p

has

e (r

ad)

–50 50–1000.0

0 100Time (fs)

Inte

nsi

ty (

arb

itra

ry u

nit

s)

S(~)z(~)

1.0

0.5

0.0800 900

Wavelength (nm)

0.6-nJ pulses 180-nJ pulses

1000800 900Wavelength (nm)

1000

NOPA2 spectrum

0.6 nJ (BBO)

WLC*

SHG 1

Oscillator CompressorStretch Yb fiber

YAG (4 mm)0.8 nJ, 0.25 ps

4 nJ, 0.25 ps1053 nm 160 fs76 MHz

250 fs11 nJ

500 kHz180 ps

Short pass (<1010 nm)

0.5

1.0 Measured (12.8 fs)

Fouriertransform

limit (11.9 fs)

A white light seeded noncollinear optical parametric amplifer (NOPA) front end can be recompressed to <13 fs

E19190t*White light continuum

**Measured using SPIDER after double-pass prism compressor

A white light seeded noncollinear optical parametric amplifer (NOPA) front end can be recompressed to <13 fs

E19190u*White light continuum

**Measured using SPIDER after double-pass prism compressor

2

–2

0

NOPA1 spectrum and phase**

NOPA1 pulse afterprism compressor

Sp

ectr

al p

has

e (r

ad)

–50 50–100

0.5

1.0

0.00 100

Time (fs)

Inte

nsi

ty (

arb

itra

ry u

nit

s)

S(~)z(~)

1.0

0.5

0.0800 900

Wavelength (nm)

0.6-nJ pulses 180-nJ pulses

160 nm

Sp

ectr

um

(ar

bit

rary

un

its)

1000800 900Wavelength (nm)

1000

NOPA2 spectrum

0.6 nJ (BBO)

180 nJ (BBO)SHG

1

2Regen Nd:YLF3.5 mJ, 10 ps

5 Hz

0.6 nJ (BBO)

WLC*

SHG 1

Oscillator CompressorStretch Yb fiber

YAG (4 mm)0.8 nJ, 0.25 ps

4 nJ, 0.25 ps1053 nm 160 fs76 MHz

250 fs11 nJ

500 kHz

Short pass (<1010 nm)

Measured (12.8 fs)

Fouriertransform

limit (11.9 fs)

TheprepulsetemporalcontrastofthefirstNOPAstageexceeds 1012 (or 120 dB) and will be further improved in subsequent picosecond-pumped NOPA stages

E19313e

• Pulsewidth(300 fs) not deconvolved from data " expect 13-dB improvement

• Artifacts(◊) are from pump postpulses (confirmedbytheirscalingwithgain)

J. Bromage, C. Dorrer, and J. D. Zuegel, presented at the International Conference on Ultrahigh Intensity Lasers, Watkins Glen, NY, 26 September–1 October 2010.

–100–200–300Delay (ps)

0 100 200

Measured NOPA1 output

Expectedoutput

Cro

ss-c

orr

elat

ion

(d

B)

–120

–140

–160

–100

–80

–60

–40

–20

0

43 dB43 dB

Cross correlator (CC)noise floor

Diagnostic artifacts

NOPA3preamplification,pulsestretchingwithadaptivedispersion control, and diagnostic compression are on track for completion this year

E20283y

*Ultra-broadband image relaying to UFE output beam shaper not shown for clarity

UFE output beam shaper*

Short pass(<1010 nm)

0.6 nJ, 0.3 ps

300 nJ, 2.5 ps

5 mJ, 2.5 ps

1 mJ, 1.5 ns

1053 nm0.16 ps76 MHz

5 Hzor 500 kHz

5 Hz

11 nJ0.25 ps

0.8 nJ0.25 ps

4 nJ0.25 ps

6 mJ10 ps

35 mJ10 ps

90 mJ10 ps

Oscillator Stretch Fiber CPA

180 ps

WLC(YAG)

NOPA1(BBO)

NOPA2(BBO)

NOPA3(BBO)

StretcherDiagnosticcompressor

Diagnostics15 fs, 0.2 mJ, 5 HzUFE

SHG(LBO)

SHG(BBO)

Nd:YLF

Dazzler

1053 nm527 nm810 to 1010 nm

A two-stage Nd:YLF pump laser produces high-energypicosecond pulses to pump NOPA2/3

E22250

• Nonlinearitymanagementintheregenerativeamplifiercompensatesself-phase modulation of picosecond pulses

• LBOprovideshighsecondharmonicgenerationefficiencyandgoodqualitybeamprofileslesssensitivetowavefronterrors

00

20

40

60

80

200Regen output energy (nJ)

AP

L21

01 o

utp

ut

ener

gy (

mJ)

400 600

527 nm

1053 nm

Regen output energy (nJ)

5-Hz flashlamp pumped laser

EKPSLA APL2101Nd:YLF amplifier

Regenerativeamplifier

• Nointrinsicchromaticaberration(Strehl 1.0)

• Beamsizeatthesecondarymirroris50× larger than a comparable spherical Offner stretcher (SOS)**

– enables50×moreshort-pulsepreamplificationtoreduceamplifiedspontaneous emission (ASE)

– reduces contrast degradation from mirror surface roughness

A cylindrical Offner stretcher* (COS) design promisesexcellent spatiotemporal performance

E20385s

*J. Itatani et al., Opt. Commun. 134, 134 (1997).**J. Bromage et al., in CLEO: Science and Innovations, OSA Technical

Digest (online) (Optical Society of America, 2012), Paper CM4D.4.

.

810 nm910 nm1010 nm

G1

G2SecondarySecondary

Input/output

Primary

Flatmirror

G1

G2SecondarySecondary

Input/output

Primary

Flatmirror

The UFE system recently moved into a new cleanroomspace to prepare for the next stage of development

E22251

MTW-OPAL will be integrated with the existing MTW Laser Systemtomaximizeexperimentalflexibility.

MTW–OPAL

MTW laser

LDL–Annex

Laser developmentlaboratory (LDL)

MTW-OPAL

MTW

LDL-Annex

Scalable OPCPA technology will be developed forthefinalMTW-OPALpulseamplificationandcompression stages

E20946c

5-Hz pump laser

15 fs, 0.2 mJ, 5 HzUFE

Short-pass(<1010 nm)

0.6 nJ, 0.3 ps

300 nJ, 2.5 ps

5 mJ, 2.5 ps

1 mJ, 1.5 ns

300 mJ, 1.5 ns

12.5 J, 1.5 ns

7.5 J, 15 fs

Co

mp

lete

dU

nd

erw

ayC

on

cep

tual

des

ign

1053 nm0.16 ps76 MHz

5 Hzor 500 kHz

5 Hz

1 shot/20 min

Single shot: 1021 W/cm2

5 Hz: 1019 W/cm2

11 nJ0.25 ps

1.6 nJ0.25 ps

4 nJ0.25 ps

6 mJ10 ps

90 mJ10 ps

Diagnostics

Diagnostics

60 J, 1.5 ns55 × 55 mm

1.5 J, 1.5 ns7 × 7 mm

Oscillator Stretcher Fiber CPA

180 ps

WLC(YAG)

NOPA1(BBO)

NOPA2(BBO)

NOPA3(BBO)

NOPA4(LBO)

Single shot:1022 W/cm2

NOPA5(DKDP)

Stretcher

Compressor

SHG(LBO)

SHG(BBO)

SHG(LBO)

SHG(DKDP)

Nd:YLF rodRegen

MTW (narrowband)

1053 nm527 nm810 to 1010 nm

Dazzler

35 mJ10 ps

DiagnosticCompressor

The MTW-OPAL project provides a platform for tackling a number of challenges for ultra-broadband lasers

E20603b

System design

Prototype testing

Optical-coating development

Phase compressionand focusing

Temporal contrast


E20603c

System design

Prototype testing



Temporal contrast

• Nanoseconddamage• Femtoseconddamage• Coatingmeasurement

• Impactofstretching/compression• ImpactofNOPAnoise• Single-shotdiagnostics

• Dispersioncontrol• Wavefrontcontrol• Single-shotdiagnostics

• High-damagegratings• Broadbandhighreflectors

with controlled dispersion• Dichroicsforpumpandsignal

• High-energyNOPA(s)• Broadbandimagerelays• Compressordesign• Beamsamplingfor

diagnostics


E20603d

• Nanoseconddamage• Femtoseconddamage• Coatingmeasurement

• Impactofstretching/compression• ImpactofNOPAnoise• Single-shotdiagnostics

• Dispersioncontrol• Wavefrontcontrol• Single-shotdiagnostics

• High-damagegratings• Broadbandhighreflectors

with controlled dispersion• Dichroicsforpumpandsignal

• High-energyNOPA(s)• Broadbandimagerelays• Compressordesign• Beamsamplingfor

diagnostics

System design

Prototype testing



Temporal contrast

NOPA5illustratessomeofkeytechnologiesrequiredtoscale ultra-broadband OPCPA to high energies

G9903a

• Ultra-broadbandbeamtransportwithdispersioncontrol

– coatings (pumpandsignal;HR,AR,dichroic,leakymirrors)

– optical image relaying systems

• Diagnostics

Calorimeter

LeakymirrorIdler

separator

SignaloutputIdler

output(s-pol)

Signalinput(s-pol)

Pumpinput

(p-pol)Dichroiccombiner

Dichroicseparator

NOPA5

6 in.

LLE has demonstrated scalable coatings that meetprimary MTW-OPAL requirements

G9902a

Highreflectors Beam combiners AR coatings Idlerfilters

•Rsignal > 99.5% (810-1010 nm)

•s- and p-polarized

•fs-LIDT>0.3 J/cm2

•ns-LIDT>2.2 J/cm2

•Dispersioncontrolled

• Rpump > 99.5% (527nm)

• Tsignal > 99%

• Signalns-LIDT >1.5J/cm2

• Pumpns-LIDT >3.6 J/cm2

• Dispersioncontrolled

• Rsignal < 0.5%

• 0°andhigh-angles-pol

• Airandvacuum

• Lenses

• DKDPcrystals

• Dispersioncontrolled

•Tidler < 1% (1100-1505nm)

•Tsignal > 95%

•Signalns-LIDT > 1.5J/cm2

•Dispersioncontrolled

Signalp-pol

Signals-pol

Pumps-pol

Idlers-pol

Four HR mirror designs have been evaluated for use ata45°angleofincidencewith15-fspulses

G9905a

• TheoreticalR%,GDD,andelectric-fieldintensity

for HR1-4

• HR1–HR3ares-polarized, while HR4 is designed for p-polarization

• HR2andHR4performwellin simulated OPAL system, including impact of residual phase errors and coating non-uniformity

• MeasuredLIDT(for coatings designed at 800 nm) indicate OPALfluencerequirementscan be met

HR1 HR2 HR3100

80

60

40

20

0

800 900 1000

Ref

lect

ivit

y (%

)

Wavelength (nm)

800 900 1000

800 1000800 1000 800 1000 800 1000

Wavelength (nm)800 900 1000Wavelength (nm)

HR4

800 900 1000Wavelength (nm)

–50

0

GD

D (f

s2) 50

100

–100

0.2

0.6

0.0

0.8

;E;2

(ar

bit

rary

un

its)

Thickness (nm) Thickness (nm) Thickness (nm)Thickness (nm)

0.4

1.0

40002000040002000020000 150010005000

225 nm 260 nm 260 nm 176 nm

48 fs222 fs2

64 fs2

CuAg;E;2max HfO2

Al2O3HfO2

Nb2O5SiO2;E;2max Nb2O5

1500 fs2

*J. B. Oliver et al., presented at Optical Interference Coatings 2013, Whistler, Canada, 16–21 June 2013.

Radial group delay (RGD) from all-refractive imagerelays can lower the peak focused intensity byorders of magnitude

E22069a

Spatiotemporal Strehl ratio (STSR)maximum intensity at optimum

defocus and time relative todiffraction-limited beam

/

0.0–400 –300 –200 –100 1000

0.5

1.0

1.5

2.0

Time (fs)

Center

Edge

Inte

nsi

ty(a

rbit

rary

un

its)

Pulse trace overlap in nearfieldfrom center to edge

Phase front Pulse front

• • •

STSR = 0.02

A systematic approach to RGD compensation andcontrol is required to achieve the desired performance

E22071a

• AnOffner-tripletdesignwithnegativelensesenablesRGDcompensationinasingle-passconfigurationwithsphericalopticalsurfaces*

– addingaspherictermstolensandmirrorsurfacesoptimizes system performance

• CompensatingtotalsystemRGDcreateslargechromaticaberrationsattheNOPA5DKDPcrystalthatdegradesconversionefficiency

Deformablemirror

(45 mm)

NOPA4-2(7.5 mm)

NOPA5(55 mm)

NOPA4-1(7.5 mm)

UFE output(3 × 3 mmsquare)

RGDCImage plane

G4(90 mm)

*S.-W. Bahk et al., presented at CLEO 2013, San Jose, CA, 9–14 June 2013.

Deformablemirror

(45 mm)

NOPA4-2(7.5 mm)

NOPA5(55 mm)

NOPA4-1(7.5 mm)

UFE output(3 × 3 mmsquare)

RGDC

G4(90 mm)

Achromatictelescope

A systematic approach to RGD compensation andcontrol is required to achieve the desired performance

E22071b

• AnOffner-tripletdesignwithnegativelensesenablesRGDcompensationinasingle-passconfigurationwithsphericalopticalsurfaces*

– addingaspherictermstolensandmirrorsurfacesoptimizes system performance

• CompensatingtotalsystemRGDcreateslargechromaticaberrationsattheNOPA5DKDPcrystalthatdegradesconversionefficiency

Achromaticsystemswillberequiredforthefinalimagerelays in the MTW-OPAL and EP-OPAL systems.

*S.-W. Bahk et al., presented at CLEO 2013, San Jose, CA, 9–14 June 2013.

AnoptimizedRGDcompensatorimprovesspatiotemporalStrehlratiofrom0.02to0.97atNOPA5

E22076a

–2

0

0

–1

–2

2

–2

0

2

–2

–2

0

0 2

2

–2

–2

0

0 2

2

0.0

–0.4

–0.2

–0.6

Wav

es

fs

cmcm

cm cm

Offner RGDcompensatorwith aspheric

correction

Offner RGDcompensator

without asphericcorrection

Residual RGD Residual wavefront SpatiotemporalStrehl ratio

0.57

0.97

S.-W. Bahk et al., presented at CLEO 2013, San Jose, CA, 9–14 June 2013.

MTW-OPAL“firstlight”isplannedfor2016whileusingnew capabilities for science as they develop

E21888a

FY13

Science with UFE

Ultra-broadbandseed or probe

15 fs, 5 Hz150 mJ

Full-energy1022 W/cm2

FY14 FY15 FY16

UFE

DesignPurchaseBuild and test

MTW-OPAL beam transport

NOPA4 pump

NOPA5 pump

NOPA4

NOPA5 amplifier

Grating compression chamber

Target chamber

fs LIDT at 905 nm

SciencePrograms

Outline

E22249b









OMEGA EP-OPAL technological challenges

E22252

• High-qualitykilojoulepumpbeams

• Ultra-broadbanddiffractiongratings

– ultra-broad bandwidth

– laser-induced damage threshold (LIDT)

– meter-scale monolithic deformable gratings

• ScalingopticalcomponentstoOMEGAEP-OPAL

– focusing optics

– large-aperture, highly deuterated DKDP

– LIDT testing

Sustained research & development is required to achieve desirable system improvements

Programmable spatial light modulator (PSLIM) systemshave been integrated into two OMEGA EP beamlines*tooptimizeoutput-beamprofiles

G9771a

• PSLIMusesaphase-onlyspatial light modulator**

– laser-beam amplitude and wavefront can be simultaneously

controlled using a carrier method

– on-shotbeam-fluenceprofile data is used to specify the beam

shaping performed by PSLIM

• Measuredinitialperformance on OMEGA EP

– IR output energy =2500J

–spatialfluencevariation= 1.34 (peak-to-mean)

Beamline IR output - PSLIM off - fluence (J/cm2)

–20 –10 0 10 20x (cm)

3

2

1

0

–15

–10

0

10

5

y (c

m) –5

15

*M.Barczyset al., presented at LASE Photonics West, San Francisco, CA, 2–7 February 2013.

**S.-W. Bahk et al., Opt. Express 18,9151(2010).

Programmable spatial light modulator (PSLIM) systemshave been integrated into two OMEGA EP beamlines*tooptimizeoutput-beamprofiles

G9771a

Beamline IR output - PSLIM active - fluence (J/cm2)

2

1

0–20 –10 0 10 20

x (cm)

–15

–10

0

10

5

y (c

m) –5

15

*M.Barczyset al., presented at LASE Photonics West, San Francisco, CA, 2–7 February 2013.

**S.-W. Bahk et al., Opt. Express 18,9151(2010).

• PSLIMusesaphase-onlyspatial light modulator**

– laser-beam amplitude and wavefront can be simultaneously

controlled using a carrier method

– on-shotbeam-fluenceprofile data is used to specify the beam

shaping performed by PSLIM

• Measuredinitialperformance on OMEGA EP

– IR output energy =2500J

–spatialfluencevariation= 1.34 (peak-to-mean)

0.0

0.5

1.5A parabolic grating wavefront

x (m)

y (m

)

–0.5

0.2

–0.2

0

0 0.5

PV = 1.5mPV = 1.5m

(nm)

Time (ps)

R80 = 16.2 nm

Focused pulse

x (n

m)

–2–50

0

50

–1 0 1 20.0

0.5

1.0(I/Imax)

A deformable-grating (DG) architecture forOMEGA EP-scale gratings has been investigated*

E22253a

*J. Qiao, J. Papa, and A. Kalb, presented at CLEO 2013, San Jose, CA, 9–14 June 2013.

• Monolithicmeter-sizegratingsare desired to improve laser-system performance

• Gratingwavefronterrorscausespatial and temporal focal-

spot degradation

• State-of-the-artwavefronterrorsare excessive for ultra-broadband pulse compression

A deformable-grating (DG) architecture forOMEGA EP-scale gratings has been investigated*

E22253

*J. Qiao, J. Papa, and A. Kalb, presented at CLEO 2013, San Jose, CA, 9–14 June 2013.

Aposition-optimizednine-actuatordeformable-grating design achieved a Fourier transform–limited pulse

x (m)0.0–0.5 0.5

9

1

84

53 2

6

7

1 23

4

5 6

78

9

0Time (ps)

1 2

R80 = 2.5 nm

–1–20.0

0.5

1.0(I/Imax)

(nm)Residual wavefront

Focused pulse

0.05

0.15

0.25

FWHM = 0.41 ps

x (m)0.0–0.5 0.5

p–v = 0.09 m rms = 0.016 m

y (m

)

–0.2

0

0.2

y (m

)

–0.2

0

0.2

x (n

m)

–20

20

0

9

1

84

53 2

6

7

1 23

4

5 6

78

9

DG actuator positions

• Monolithicmeter-sizegratingsare desired to improve laser-system performance

• Gratingwavefronterrorscausespatial and temporal focal-

spot degradation

• State-of-the-artwavefronterrorsare excessive for ultra-broadband pulse compression

Anultra-broadbandhigh-reflectorcoatingforanoff-axisparabola poses design and manufacturing challenges

G9909a

• Curvatureofthemirrorleads to varying coating thickness across the part

– 10-mm sag yields >3% coating nonuniformity

• Spatiallyconsistentgroup delay is essential to maintain pulse width

• Customchambergeometry may be necessary to radially

adjust thickness

• Metalliccoatingswithlow group delay simplify the solution (but with lower damage threshold)

*J. B. Oliver et al., presented at Optical Interference Coatings 2013, Whistler, Canada, 16–21 June 2013.

Laser-induced damage testing (LIDT) with femtosecondpulses from NOPA4 will support optics development

E22254

• LIDTtestingwithsmallspots (<1-mm-diam) at the OPAL use wavelength

– initiallytestsamplesinair; ultimately test in vacuum

– test samples in 1-on-1 and N-on-1 regimes

• Potentialforcollaborationswith other interested research groups

UFE810-1010 nm

1.5 ns (stretched)

NOPA 4

NOPA 5

Compressto 15 fs

7.5 J, 15 fs,1022 W/cm2

MTW pump

≥5-Hzpump laser

UFE810-1010 nm

1.5 ns (stretched)

NOPA 4

NOPA 5

Compressto 15 fs

7.5 J, 15 fs,1022 W/cm2

150 mJ, 15 fs5 Hz or single shot

≤1022 W/cm2

MTW pump

≥5-Hzpump laser

E22254a

Laser-induced damage testing (LIDT) with femtosecondpulses from NOPA4 will support optics development

• LIDTtestingwithsmallspots (<1-mm-diam) at the OPAL use wavelength

– initiallytestsamplesinair; ultimately test in vacuum

– test samples in 1-on-1 and N-on-1 regimes

• Potentialforcollaborationswith other interested research groups

Upgrading OMEGA EP to pump an exawatt-classOPCPA system is a long-term goal

E22255

LLE is developing OPAL technology to support ultrahigh-intensityresearchthatcancapitalizeontheexistingOMEGAEPfacility.

FY13 FY14 FY15 FY16 FY17 FY18 FY19 FY20 FY21 FY22

MTW-OPAL develop/build

MTW-OPAL science MTW-OPAL science (continued)

Pre-CDR OMEGA EP-OPAL design

OMEGA EP-OPAL build

UFE

project

E22248

Summary/Conclusions

Ultra-intense laser development at LLE is aimed atscaling technologies for an exawatt-class facility

• TheLaboratoryforLaserEnergetics(LLE) operates the Omega Laser Facility to provide high-energy kilojoule (kJ), nanosecond, and picosecond laser pulses for a wide range

of user experiments

– prototype systems, used to demonstrate key technologies, also provide a platform for ongoing research and development

• Ultra-broadbandopticalparametricamplification(OPA) pumped by kilojoule-class lasers offers a promising approach to achieve focal intensities up to 1024 W/cm2

– scalable technologies are being developed in an OPA line (OPAL) pumped by the Multi-Terawatt laser (MTW-OPAL)

An exawatt-class upgrade to OMEGA EP is a long-term goal.

Documents

Technology Development and Prospects for Exawatt-Class