Laser Chain status:Amp1 &Harmonic generation

detailsMassimo Petrarca & Marta Divall

First Amplifier layout

M1

M2

M3

M4

M5

1st pass2nd pass3rd pass

F1 = +1146mmPreamp. beam

58cm54cm

21cm3.5cm 2.5cm

5cm

M6 Nd:Ylf rod

-After the discovery of Amp1 problems (thanks to harmonic generation + scope) the Amp1 design has been revised and changed: 3 different configuration.

-Final configuration: 3 passages trough the rod with F1 to ~ compensate for the beam divergence: X(3rd pass)-X(1st pass)~1.2mm; Y(3rd pass)-Y(1st pass)~1mm . Nominal power ~3KW has been reached with 85ampSatisfactory trace pulse stability has been reachedTransverse beam parameters:M2

x~2.38; M2x~1.94

M1

M2

M3

M4

M5

1st pass

2nd pass

3rd pass

F1 = +1146mm

Preamp. beam

58cm54cm

21cm

3.5cm2.5cm

5cm

Camera

X=1.439 mm

Y=1.323 mm

X=1.579 mm

Y=1.432 mm@ 50a

@ 60av

@ 80a@ 70a

X=1.698 mm

Y=1.544 mm

X=1.800 mm

Y=1.685 mm

Imaging the rod center

Imaging lens

Looking at the amplification processBy imaging the transverse beam profile in the rod

Along the 3rd passageF = +20cm

Magnification=78/27~2.8 @0amp

Temporal Profile & Power

M1

M2

M3

M4

M5

1st pass2nd pass3rd pass

F1 = +1146mmPreamp. beam

58cm54cm

21cm3.5cm 2.5cm

5cm

M6 Nd:Ylf rod

Power Masurements:

Unamplified ~ 5.4 W@ 50 amps ~ 6.6 W@ 60 amps ~ 7.5 W@ 70 amps ~ 8.4 W

@ 80 amps ~ 9.4 W ~2.75 KW@ 85 amps ~ 9.9 W ~3.1 KW

Temporal Profile after Pockel Cell

Macro pulse window selection by Pockels Cell

Leading edge from Pockels Cell

Trailing edge from Pockels Cell

Selected window edge from Pockels Cell

Amp1 Harmonic GenerationIR energy within 2s

gate

GREEN energy

within 2s gate

UV

Energy within

2s gate

Amp1 @80amps

PC on 2s

( Best Result )

(3.97-1.3)mJ

std=0.02mJ

1.170 mJ

Std=0.16mJ

0.398 mJ

Std=0.012

133.3 nJ in a micro pulse

~44 % efficiency

~34 % efficiency

Amp1 @80amps

PC on 2s

(4.15-1.33)mJ

std=0.06mJ

1.15 mJ

Std=0.05mJ

0.375 mJ

Std=0.02

123.3 nJ in a micro pulse

Satisfactory conversion efficiency values has been achieved either for SHG and FHGobtaining a final micro pulse energy of ~120 nJ with only AMP1 working at 80amps

Next

- Synchronization

- Second amplifier optimization

- Harmonic conversion with second amplifier on

-……