Tsunami - Beckman Institute Laser Resource Center

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Tsunami
Typical Set-ups
Example 1 : Synchronizing Pulses from
Two LTC Tsunami Lasers
A typical experiment set-up is shown in Figure 8-6. Tsunami "A" is the
master oscillator, and the 80 MHz REF OUT from its Model 3930 Lok-to-
Clock electronics module is used for the Model 3930 REF IN signal of
Tsunami "B." The output beams of both lasers are combined and
overlapped as shown in the figure.
In an experiment using synchronized pulses from two LTC Tsunami lasers,
the timing function (using either the manual TlMlNG controls or the sweep
generator) facilitates locating your pulses by adjusting the timing of one
pulse with respect to the other. Use the sweep to find the pulses, use the
TlMlNG controls to overlap them. Note: modifying the laser frequency by
50 Hz is equal to about 1 Fm of motion at mirror MI.
1. Adjust each Tsunami laser for optimum performance at the desired
wavelengths.
2. With each Model 3930 unlocked (there are no illuminated segments
in either STATUS display), place a photodiode (e.g., an ET2000) at the
source of the experiment.
3. Adjust the optical alignment so the pulse train for each Tsunami laser
can be identified.
4. Set up and lock Tsunami "A" as outlined in "Operation Notes" above.
5. Repeat step 4 for Tsunami "B."
The oscilloscope display should now show two pulse trains with a fixed
delay. The pulse trains are now synchronized, but are probably not
overlapped in time.
6. Verify the time between the pulse trains can be varied by using the
coarse TlMlNG control.
The TlMlNG control on each system provides up to 2 ns of adjustment.
If the pulses are more than 2 ns apart, change the length of the cable
between the two Model 3930s (30 cm of cable corresponds to about 1
ns of delay). Do not modify the cables between the laser head and the
Model 3955! When the cable length is optimized, activate the sweep
generator (by pressing the TlMlNG button) on the Tsunami "B" Model
3930 and observe the pulses from Tsunami "B" sweeping back and
forth over those from Tsunami "A."
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