High energy classsecond harmonics generationfrom CLBO by 20-J DPSSLTakashi Sekine, Hiroshi Sakai, Yasuki Takeuchi, Yuma Hatano, Toshiyuki Kawashima, Hirofumi Kan

7th International HEC-DPSSL Workshop

September 14, 2012

Lake Tahoe, California

HamamatsuHamamatsu Photonics K. K.Photonics K. K.

Outline

• Introduction of Hamamatsu Photonics K. K.

• HALNA program at ILE, Osaka University

• KURE-I green DPSSL by CLBO at Hamamatsu

• Summary

Introduce of Hamamatsu-City

Tokyo

Fukushima

Hiroshima

Osaka

Osaka

Tokyo

300km

NagoyaMt. Fuji

Shinkansen

300km

Hamamatsu

Industries in HamamatsuAuto mobile: SUZUKI, HONDA, Yamaha Motor

Musical instrument: KAWAI, Roland, YAMAHA

Photonics device: Hamamatsu Photonics

Established: September, 1953Established: September, 1953Capital: 34 billion yenCapital: 34 billion yenSales: Sales: 10100 billion yen0 billion yenEmployee: 4,100Employee: 4,100

Profile of Hamamatsu Photonics group

We have played a role in Neutrino ScienceWe have played a role in Neutrino ScienceThe Kamiokande captured the total of 1016

neutrinos that passed through the detector.This has led to unexpected discoveries and a new, intensive new field of research, neutrino-astronomy. The Super-Kamiokande, and the consequent KamLAND also equips the improved HAMAMATSU photo-multiplier tubes.

Kamioka Observatory, ICRR（Institute for Cosmic Ray Research）, The University of Tokyo

Photo-multipliers

Semiconductor lasers

Photo-sensors

Optical measurement Medical diagnostics

Products of Hamamatsu Photonics

Laser system products Direct Diode Laser Fiber out Laser Diode Quantum Cascade Laser

Stealth Dicing LaserFiber Disk Laser Pico-second Laser

Direct processing

of atoms

Neutron generation

Annealing

Dicing

10-15 10-12 10-9 10-6 10-3 1

Pow

er d

ensi

ty (W

/cm

2 )

1021

1018

1015

1012

109

106

103

Drilling

Non-thermal

processing

Cutting, Welding

Hardening

Pulse width (ns)

Peening

IFEIFE

Continuous wave

Single pulse

Repetitive pulse

HECHEC--DPSSLDPSSL

Development of Photonics Industriesby DPSSL at Hamamatsu

CuttingCurrent

Inertial Fusion

Welding

Wafer dicing

Si annealing

Future

Neutron therapy

Neutron imaging

Transmutation

Next

Conceptual design of HALNA ILE OSAKAILE OSAKA

HALNA 10 (8.4 J in 20 ns at 10 Hz)Glass volume:2.2cm x 1cm x 40cm(1 slab)Stored at 0.4 J/cm3

HALNA 100 (100 J in 10 ns at 10 Hz)(December 2004) (Current status)

Glass volume:10cm x 1cm x 40cm(2 slabs)Stored at 0.4 J/cm3

Half scale (21.3 J in 8.9 ns at 10 Hz)

ILE OSAKAILE OSAKAILE OSAKA

Current status of HALNA

5 cm x 1cm x 40cm(2 slabs)Stored at 0.2 J/cm3

Diode pumped green laser KURE-I

>10%Opt. to opt. eff.

>14JOutput energy10 HzRepetition rate527 nmWavelength>70%

Specifications

SHG conv. eff.

Nd:YLF regen.amplifirier

Yb:fiberoscillator

Deformable mirror

Up collimating telescope

Image-relaying telescope / Spatial filter

Diode-pumpedslab amplifier

Beam shaping

Faraday rotator

Faraday isolator

Laser output

再 生 増 幅 部

発 振 器 部

主 増 幅 部

波 長 変 換 部

Frequency doublerRegen.

Amp.

Osc.

Detail layout of Main Amp.

SHG

KURE-I system

Pre. Amp. LD module Main laser head

Deformable mirror

Frequency doubler

Peak power 200kW/moduleWavelength 803 nmEfficiency > 50%

Current status of fundamental output

0

5

10

15

20

25

30

0 20 40 60 80 100 120 140 160

LD current (A)

Out

put e

nerg

y (J

)

0.0

0.2

0.4

0.6

0.8

1.0

Extraction efficiency

CalculationExperiment

Repetition rate:1 Hz

21.4 J1 HzRepetition rate

41.6%Extraction eff.14.7%Opt. to opt. eff.

Output energyFFP

NFP

Design>20% at 32J output with 160J pump

Strong

5.6

43>500.95

CLBO

StrongSlightlyNonHygroscopicity

1.3

65>800.91

YCOB

5.51.1Spectral bandwidth (nm)

6.755Temperature bandwidth (deg.C)

0.41.94Effective nonlinear coefficient (pm/V)~30

BBO

>400Maximum aperture (mm)

DKDP

Characteristics of CeLiB6O10(CLBO) nonlinear crystal

CLBO ingot Cut and polish N2 purged mount40mm

40m

m

14mmtNon AR coatingon the CLBO’s face

Design of frequency doublerEvaluation of phase mismatch

V.G.Dimitriev et. al. , "Handbook of Nonlinear Optical Crystals"1 W/mKThermal conductivity

70%SHG conv. eff.

0.001 cm-1Absorption coefficient

20 JInput energy

10 HzRepetition rate

10 ns (FWHM)Pulse width (Gaussian)

0.2 mrad

Design parameter

Angular mismatch

0 angl spec thempk k T

Frequency conversion sensitivity

angle spectrum temperature

1.772L Bandwidth

Bandwidth

Second

harmonics

Temperature

z:Position in lenagth

Face cooling

Fundamental

Line width

Nonlinear Crystal

Incident angle

Beam divergence 0

0.2

0.4

0.6

0.8

1

0 2 4 6 8 10 12 14 16 18 20Crystal length (mm)

Con

vers

ion

effic

ienc

y

Fiber laserbased frontend

LD pumped Nd:YLF ring preamplifier

LD pumpedNd:glass zig-zag

slab main amplifier

CLBO frequency doublar

Output

AT

VSF

VT

CCD HA

DM1DM2

IP

IP IP IP

IP

IP CLBO

QR

WBD

EM1

EM2Input

BD

16mm

22m

m

8mm

44m

m

Optical setup of SHG and diagnostics~nJ 300mJ 20J 14J

02468

10121416

0 5 10 15 20Fundamental pulse energy (J)

Seco

nd h

arm

onic

puls

e en

ergy

(J)

00.10.20.30.40.50.60.70.8

Conversionefficiency

0

256

64

192

128

Output characteristics of SHG

There is no significant reduction of conversion efficiency by exposing over 600,000 shots fpr intermissive experiments during 3 years.

Filling factor:44.2%

•NFP

•12.5 J with 71.5%

0.1 mradBeam divergence

0.1 mradAngular mismatch

SingleLongitudinal mode

10 HzRepetition rate

10 ns (FWHM)Pulse width (Gaussian)

10 cm x 10 cmBeam size

0.0013 cm-1

(Assumed same with DKDP)Absorption coefficient at 1um

1.25 W/mK(Assumed same with DKDP)

Thermal conductivity

9 mmCrystal length

Type-IIPhase match type

CLBOParameter

Prospect of kJ class SHG by CLBO

0

0.2

0.4

0.6

0.8

1

0 200 400 600 800 1000Input energy (J)

Con

vers

ion

effic

ienc

y

CLBO 10Hz Rep.

CLBO Single shot

SummarySummary

• CLBO frequency doubler has been developed for HEC-DPSSL.

• 12.5 J with 71.5% conversion efficiency has been demonstrated.

• Prospect of frequency converter for 1 kJ x 10Hz by CLBO was evaluated.