Laser stability

Takuya Natsui

Oscillator phase lock stability

Cavity length drift Phase lock stability PriceMenlo products << 0.1 um 0.0 (detection

limit)$ 150000

(1800 万円 )Oscillator 1 3 um 2.0 deg $ 35000 (400万

円 )Oscillator 2 1 um 0.58 deg $ 35000 (400万

円 )Oscillator3ANDi type

1 um 0.64 deg $ 35000 (400万円 )

Stability： 0.58 deg

Stability： 0.64 deg

Stability： 2.0 deg

Piezo position (cavity length drift)

Oscillator phase lock system

Zurich Instruments UHFIL Lok-in Amplifier

Stability: 1.5 deg in 2856 MHz

0.3 deg in 571 MHz

0.056 deg in 114 MHz

Commercial products also tested

Developed synchronization system Commercial products

Stability: 1.5 degStability: 0.64 deg

Compared in same oscillator, developed synchronization system has enough capability.

$10000 $60000

laser operation log

Laser system and detect point

Yb-doped fiber oscillator with

Transmission grating

Yb-doped fiber pre amplifier

Yb-doped fiber main amplifierPulse picker

Yb:YAG thin-disk multi-pass cavity amplifier

Yb:YAG thin-disk multipass amplifier ×3

SHG

Synchronization system

SHGRF GUN

51.9 MHz

2, 5, 25, 50 HzSingle or Double bunch

0.2 nJ @ 1037 nm

Yb-doped fiber main amplifier

Transmission grating pair

stretcher

2856 MHz triggerFrom Accelerator

Yb-doped fiber pre amplifier

>μJ @ 1037 nm

Pulse picker

10 MHz

Fix the configuration to 25 Hz operation

PD2PD1

PD3

PD4

Power meter

We have five constant monitoring points.Photo diode x4, Power meter x1

Detector (photo diode)

Laser pulse power is detected with photo diodes and oscilloscope.

start-up

First, fiber amplifier drifts

Fiber amp.

Disk amp.1

Disk amp.2

Disk amp.3

Laser is stabled gradually

Sometimes fiber amplifier drifts

Disk amplifier is damaged

Recently, 1 or 2 days stabilization was achieved.

FixDisk amplifier is damaged

BPM error

Recent operation log

We achieved two days stable operation.

(0.7 +/-0.3 nC)

BBO

Fundamental laser power

Beam charge

Still long term drift occur.

We will increase detection points. Develop power feed back systems.

Pointing stability detector is also developing with quadrant sensor.

52 MHz

2856 MHz

INPUT 1

INPUT 2

INPUT 3

INPUT 4

2856 MHzBPF

52 MHzBPF

Oscillator signal

Oscillator phase detect

52 or 114 MHz IQ signal

2856 MHz IQ signal