Spectra-Physics Tsunami - Changing Prism Settings (fs Systems)

Tsunami Mode-Locked Ti-sapphire Laser
6-30
10. Replace M
2
.
a. Unscrew the M
2
holder and replace the optic in the holder with the
appropriate one for the chosen wavelength. Screw the holder back
in.
b. Adjust
M
2
vertically and horizontally until the fluorescent images
are again overlapped on
M
5
.
c. Verify the cross image is also visible on the card outside the output
window.
11. Replace M
3
.
Adjust P
2
vertically and horizontally until the fluorescent images are
once again overlapped on M
5
. Slight adjustments to M
3
might be
required to direct the fluorescence from M
1
and M
3
back to the card
outside the output window.
12. For fs systems, replace M
4
through M
9
with the new optics; for ps sys-
tems, replace M
4
and M
5
.
Change optics in sequence, one at a time, adjusting each to obtain the
cross image on the white card outside the output window before mov-
ing on to the next optic.
13. Replace M
10
.
a. Reach in from both sides of the M
10
mount and unscrew the knurled
mirror holder (Figure 6-13).
b. Replace the optic in the holder with the new one and screw the
holder back in.
14. Align M
10
.
a. Place a white card with a 2.5 mm diameter hole in it between M
4
and M
5
so the hole is centered on the reflected fluorescent image
from M
4
.
b. Direct the reflected image from M
10
back through the hole in the
card and overlap it with the image from M
4
.
When you remove the
card, lasing should begin.
To determine which reflected image comes from M
10
, watch the
output side of the card and slightly adjust
M
10
until one image
moves.
c. Remove the card.
15. Replace the card in front of the output window with a power meter.
16. On ps systems, reinstall and align the bi-fi according to the section
“Selecting, Installing and Aligning the birefringent Filter” earlier in
this chapter. When the bi-fi is installed, you are done.
Changing the Prism Setting (fs Systems Only)
If you have a Model 3950 ps-only laser without prism mounts, skip to Step 6.
Due to the difference in the index of refraction for the different wave-
lengths, the intracavity beam will be either too high or too low on prisms
Pr
2
and Pr
3
when you change wavelength ranges and it is necessary to