Tsunami - Beckman Institute Laser Resource Center

Tsunami
To measure pulses, use a Spectra-Physics Lasers Model 409 -08 autocorrelator
(or equivalent). Avoid saturating the autocorrelator. Subtle
adjustments to the phase-matching angle of the nonlinear crystal will
be required to obtain an optimum autocorrelation signal. Refer to the
autocorrelator manual for setup and operation instructions.
3. Open the pump and Tsunami shutters and adjust the pump laser until
your Tsunami achieves the output power specified in Table 3-1 or
Table 3-2.
4. Test for proper mode locking.
Aligning the A10 Modulator (AOM)
While watching the pulse on the oscilloscope, block the intracavity beam
for a couple of seconds with a card, then remove the card.
If the mode locker system is operating properly, the pulse on the oscilloscope
should return immediately. If it does, you do not need to
align the AOM and cavity alignment is completed.
If there was no pulse initially, or if the pulse did not return after interrupting
the intracavity beam, continue with "Aligning the A10
Modulator (AOM) .
The photodiode alignment earlier in this chapter must be performed before
you align the AOM. It assures a maximum photodiode signal for reliable
mode locking.
Proper AOM alignment is critical for both ps and fs Tsunami lasers. The
following procedure assures good AOM beam alignment for optimum
mode locking. Figure 5-3 is a system interconnect diagram to assist you in
verifying correct cable connections. Figure 6-12 shows the location of the
AOM.
1. Verify the output beam is centered on Mlo.
Place a white card between M10 and the beam splitter, and use the
edge of the card to detect the position of the beam.
2. Using the vertical control knob of MI0, detune the laser until it stops
lasing.
3. Verify the intracavity beam is centered in the AOM.
Use an ir viewer to see that the M3/M1 fluorescence is centered
through the silhouette of the AOM crystal. The fluorescence should
not be near the edges of the crystal. If necessary, loosen the AOM
mounting bracket to adjust it vertically and horizontally. Two 2-56
setscrews hold it horizontally while two in. cap screws keep it
secured vertically.