Tsunami - Beckman Institute Laser Resource Center

Tsunami
Mode Locking the Laser
6. When the laser is optimized in the vertical direction, repeat steps 3
through 5 using the horizontal controls.
7. If necessary, recenter the beam on Mlo. Carefully adjust M3 (and M4
and M5 if necessary), then adjust Mlo to maximize output power.
8. To recenter the beam on MI, carefully adjust MP. Then again adjust MI
to maximize output power.
9. Repeat this entire procedure, starting at step 3, until no further
increase in power is noted.
This completes the procedure for "walking the beam" to optimize laser
output. Continue on to "Mode Locking the Laser."
Proceed to mode lock the laser once the pump laser and the Model 3955
are wanned up.
1. Push the STATUS mode locker enable button (the ENABLE LED should
be lit).
The two TEMPERATURE indicators on the Tsunami laser control panel
turn from red to green when the AOM and GTI (ps configuration)
heaters stabilize. Proceed to step 2 when the indicators are green.
AJZashing red indicator means either: (a) the GTI is not installed
(normal for fs configuration) or (b) there is an unplugged cable.
2. To measure the Tsunami output pulse width, use an autocorrelator
such as a Spectra-Physics Lasers Model 409. Avoid saturating the
autocorrelator (refer to the autocorrelator manual).
For a brief discussion on autocorrelation and measuring pulse widths,
refer to appendix B, "Pulse Width Measurement."
Skip to step 4 if you just optimized output power in the previous section.
3. Maximize Tsunami output power.
Place a power meter in the Tsunami beam path and adjust Mlo and MI
for maximum output power.
4. Adjust the autocorrelator for maximum signal.
5. Adjust the mode locker fine PHASE control for shortest pulse.
If laser output pulses are not present, adjust the fine PHASE control on
the Model 3955 electronics module until either a short pulse appears
on the oscilloscope or the autocorrelator signal is maximized.
If you are using cables other than those shipped with the system, or if
you converted the laser from a ps to a fs configuration, or vice versa,
or if you changed optics sets, the phase signal may have moved
outside the range of the fine PHASE control. If this seems to be the