Alignment
6-35
To convert the Tsunami from fs to ps operation requires the following:
• Changing output coupler M
10
.
• Removing the tuning slit and adding the appropriate bi-fi into the cav-
ity.
• Moving Pr
1
and Pr
4
out of the beam path.
• Replacing the high reflector at
M
1
with the GTI.
To convert from ps to fs operation, simply reverse this procedure.
Fs to ps Conversion
The following procedure assumes you are using the same set of optics
(same wavelength set) or an overlapping wavelength optics set.
Verify the Tsunami laser is lasing prior to beginning this procedure, and
maximize its output power.
1. Close the pump laser shutter.
2. For electrical safety, turn off the Model 3955 electronics module.
3. Remove the high reflector assembly.
a. Loosen the three screws holding the high reflector mounting ring
in the rear mirror plate, and turn the three D-shaped cam locks so
the flat portion of the cam disengages the mounting ring. The high
reflector assembly is removed in a manner similar to that for the
GTI shown in Figure 6-21.
b. Pull the high reflector assembly with its mounting ring from the
rear mirror plate and store it in a safe place.
4. Install the
GTI into the M
1
position (Figure 6-21).
Refer to Chapter 5, “Installation: Installing the GTI.”
5. Turn on the Model 3955 and allow about 20 minutes for the
GTI and
AOM to warm up.
You may continue with the installation while waiting for the optics to
warm up and stabilize.
6. Open the shutter, and reestablish lasing.
a. Place a white card in front of mirror
M
5
.
b. Using an IR viewer, adjust
M
1
vertically and horizontally to overlap
the reflected horizontal oval fluorescent image onto the vertical
oval from M
3
as seen on the white card. A cross-shaped image
results (Figure 6-6).
c. Remove the card: lasing should begin.
7. Adjust the laser for maximum output power.
When changing between fs and ps measurements, the scan range of the
Spectra-Physics Model 409-08 autocorrelator must be modified in order
to accommodate for the large change in pulse width. Consult your auto-
correlator manual for this procedure.
Note
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