Tsunami - Beckman Institute Laser Resource Center
Tsunami - Beckman Institute Laser Resource Center
Tsunami - Beckman Institute Laser Resource Center
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Chapter 7<br />
Operation<br />
System Start-up<br />
Once the <strong>Tsunami</strong> laser has been installed and aligned, we suggest you<br />
leave the Model 3955 and optional Model 3930 electronics modules on at<br />
all times. The day-to-day operation is then consistent and repeatable. Provided<br />
nothing is disturbed between operating sessions, only minor adjustments<br />
and purging are required to return the <strong>Tsunami</strong> laser to optimum<br />
performance levels.<br />
1. If not already on, turn on the Model 3955 electronics module.<br />
It takes about 20 minutes for the acousto-optic modulator (AOM) and<br />
GTI @s configuration) to reach operating temperature. If your system<br />
includes the optional Lok-to-Clock" system, refer to chapter 8,<br />
ccLok-to-Clock: Operation," for start-up information for the Model<br />
3930. In the meantime, continue with system start-up.<br />
2. Verify the pump laser shutter is closed, then turn on the laser and set it<br />
for its anticipated power level.<br />
Allow it to warm up according to its instruction manual. Continue with<br />
start-up while these systems are warming up.<br />
3. Verify the <strong>Tsunami</strong> optics are clean.<br />
If the cover was left in place and the system was purged the last time<br />
it was used, it is safe to assume the optics are still clean. If you are not<br />
confident that this is the case, remove the cover for inspection. If they<br />
are dirty, refer to chapter 9, "Maintenance," for information on cleaning<br />
optics.<br />
4. Turn on the chiller according to its instruction manual and verify its<br />
temperature is set for 18" C (64°F).<br />
5. Begin the dry nitrogen purge.<br />
The Model 3910 regulatorlfilter purge unit is provided for use with<br />
bottled nitrogen gas to eliminate problems associated with dust, contamination<br />
and the tuning discontinuities caused by oxygen and water<br />
vapor. The latter exhibits strong absorption lines in the long wavelength<br />
region between 840 - 1000 nm, especially at 944,950,98 1.2<br />
and 984.1 nrn (Figure 7-1). Due to the strength of these absorption<br />
lines, the moisture level within the laser head must be below 1000<br />
ppm to allow problem-free mode locking. For these wavelengths, we
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