CTF3 CTF3 Laser StatusLaser Status

Massimo PetrarcaMassimo Petrarca

CLIC January 23 2008

3-pass Nd:YLF amplifier

x300

3 pass Nd:YLF amplifier

x5

Probe Beam

General LASER General LASER LayOUT:LayOUT:

Optical gate (Pockels cell)24

UV pulses

1.24 s

Drive BeamBrewster plate

1.5 GHzNd:YLF

Oscillator

1.5 GHzNd:YLF

preamplifier

PhaseCoding

Micro pulses at 1.5 GHz~666ps

400us amplification windowfor AMP1

Macro pulse

200us amplification windowfor AMP2

Macro pulse

General pulse structure General pulse structure layoutlayout

not in scalenot in scaleOscillator

& Preamplifier

1.5 GHz; 10W AVG

Power

AMP1 @ 90A400 us;

5Hz 3KW Peak

Power

AMP1 + AMP2@90 A

400 us;200us5Hz

14 KW Peak Power

400us amplification windowfor AMP1

Macro pulse

200us amplification windowfor AMP2

Macro pulse

Micro pulses at 1.5 GHz

~666ps

Step by Step characterizationStep by Step characterization

Time structure (3 passes configuration) of the macro pulse coming out of AMP1

Power, Energy Measured @ 90A

Zoom in

The peak power of the macro pulse thus the the gain and micro pulse energy

are well above the specs

1.5 GHzNd:YLF

Oscillator+preamplifier

3-pass Nd:YLF amplifier

400 s, 5 Hz

diode pump 15 kW

Project specification:~3 kW ; 2 J/pulse 3 pass Nd:YLF

amplifier

diode pump 5 Hz

Step by Step characterizationStep by Step characterization

Time structure (2 passes configuration):Gain, Peak Power and Energy when AMP1 and AMP2 are both

90A

1.5 GHzNd:YLF

Oscillator+preamplifier

3-pass Nd:YLF amplifier

400 s, 5 Hz

diode pump

3 pass Nd:YLF amplifier

5 Hz

diode pump

Project specification:~15 kW ; 10 J/pulse

Which is the expected value for the amplifier output power when diode arrays are driven by 90amps current (18 KW

pumping power) each?

3-lens system with 1.2 magnification yields a good matching between the

transverse beam size of the beam and the rod.

Preamplifier & AMP1 output VS

Oscillator

0

2

4

6

8

10

12

0 100 200 300 400

Oscillator Power, mW

Am

plif

ier

po

wer

, W

Preamp power, W

Amp1 power, W

1.5 GHzNd:YLF

Oscillator

1.5 GHzNd:YLF

preamplifier

PhaseCoding

3-pass Nd:YLF amplifier

x300

AMP1 behavior vs

oscillator input power

In order to obtain an AMP1

satisfactory power response

an oscillator power

of at least 36 mW is needed.

AMP1 power for 288mW oscillator output

0

500

1000

1500

2000

2500

3000

3500

4000

200 300 400 500 600 700 800 900

Time, us

Po

wer

, W

AMP1 power for 36 mW oscillator output

0

500

1000

1500

2000

2500

3000

3500

4000

200 300 400 500 600 700 800 900

Time, us

Po

wer

, W

AMP1 oscillation behavior vs

oscillator input power

In order to obtain an AMP1 satisfactory power response an oscillator power of at least 36 mW is

needed, but oscillation in the beam intensity increases the oscillator output power limit from

36mW to 82 mW

AMP1 power for 82 mW oscillator output power

0

500

1000

1500

2000

2500

3000

3500

4000

200 300 400 500 600 700 800 900

Time, us

Po

we

r, W

ConclusionConclusion::

• The power of the first amplifier is satisfactory as well as The power of the first amplifier is satisfactory as well as the time structure (saturation region). Its transverse beam the time structure (saturation region). Its transverse beam

profile has to be optimize profile has to be optimize • Regarding the second amplifier:Regarding the second amplifier:

the power is still not satisfactory for the specification of the the power is still not satisfactory for the specification of the project. Which should be the value for the pumping power project. Which should be the value for the pumping power in order to obtain the 15 KW of the amplified beam? (Talk in order to obtain the 15 KW of the amplified beam? (Talk

to RAL). The transverse beam profile is satisfactory to RAL). The transverse beam profile is satisfactory comparing it with the beam profile of the input (into comparing it with the beam profile of the input (into

AMP2).AMP2).• Investigation of the oscillation in the amplified beam for Investigation of the oscillation in the amplified beam for

36mW of input power into the preamplifier must be done: 36mW of input power into the preamplifier must be done: are the oscillation causes by instability of the preamplifier are the oscillation causes by instability of the preamplifier

or by AMP1? or by AMP1? • Pockels cell is installed and works properly.Pockels cell is installed and works properly.

• Installation of the quadrupling crystals will be done in few Installation of the quadrupling crystals will be done in few days. days.

The End