Service and Repair
11-3
Symptom: Low output power
Possible Causes Corrective Action
Insufficient pump power. Adjust pump power to:
∼8 to 10 W for a 10 W pump configuration.
∼5 W for the > 5 W pump configuration.
Chiller mishap or is not on. Turn on the chiller.
Check that the reservoir water level is filled to the proper level.
Check temperature setting; should be set to 18° C.
Check for a water flow obstruction in the chiller and Tsunami laser head.
Tsunami is not optimized. Adjust M
1
and M
10
as described in Chapter 6, “Alignment: Cavity Alignment.”
If these adjustments fail to restore output, refer to the next cause below.
Optics are dirty. Inspect the optics for dirt or contamination. If dirty, clean the optics using the
cleaning procedure in Chapter 9, “Maintenance.” If an optic is dirty, an IR
viewer will show unusual scatter.
System is not properly aligned. Check that the pump beam is centered on M
2
and M
3
(the side facing the
Ti:Sapphire rod). Avoid parallax error.
Check for beam centering on mirrors M
1
through M
5
, prisms, AOM and OC.
Check for the location of the cavity beam on M
6
through M
9
(M
8
should be a
mirror image of M
7
).
SF-10 prism (G0360-000 (apex ∼60° 42’)) use in systems without the Blue
set, a must for X-long systems.
At 800 nm, the beam should be centered on M
7
and M
8
.
LaFn28 Prism (G0383-000 (apex ~ 59° 15’)) used in Blue, Broadband and
USP options.
At 800 nm, the beam should be
3
/4 of the way toward PR
2
/Pr
3
assembly.
Slit width too narrow
(Femto configuration only)
Slit width should be 2.2 mm > x > 1.33 mm. Proper slit width depends on
pump power and the amount of prism glass in the cavity (dispersion con-
trol).
Poor pump laser mode quality. Check pump laser power and mode (requires TEM
00
pump mode).
Dirty optics and/or beam split-
ters in the pump laser.
Clean the optics if necessary. Refer to the cleaning procedure in the pump
laser user’s manual.
Wrong optic(s) in the cavity
and/or cavity location.
Verify that all cavity optics are correct to their location according to Table 10-
10 in Chapter 10.
Symptom: Laser will not mode lock
Possible Causes Corrective Action
Model 3955 electronics module
is not on.
Turn on the electronics module. Enable the RF by pushing the STATUS but-
ton. For pico configuration, it is necessary to wait > 20 minutes to allow the
GTI to warm up for stable dispersion compensation.
RF power is not enabled. Enable the RF by pushing the STATUS button.
Chiller mishap or is not on. Turn on the chiller.
Check that the reservoir water level is filled to the proper level.
Check temperature setting; should be set to 18°C.
Check for a water flow obstruction in the chiller and Tsunami laser head.
Wavelength on or near water or
oxygen absorption lines.
Consult Chapter 7, “Operation,” Figure 7-1 for the location of water and oxy-
gen absorption. Purge when necessary.
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