Tsunami - Beckman Institute Laser Resource Center

I1 I1 Il i l l ! iil lll,,,ll C I I, 111 I ll l I
Alignment
10. Remove the M4 mirror holder from its fs mount position and install it
into the ps mount near the output end of the laser head (Figure 6-8). Do
not relocate the mounts.
11. In like manner, remove the M5 mirror holder from its fs mount position
and install it into the ps mount near the input end of the laser
head (Figure 6-8).
Note: these last two steps are required to reestablish correct cavity
length now that the prisms are out of the beam path. These mirror positions
were preset at the factory.
12. Verify the fluorescence from M4 is centered on M5.
If not correctly positioned, adjust M4 vertically and horizontally until
it is. If you adjust M4, readjust M5 to recenter the beam from M5 on the
AOM.
13. Place a white card outside the output window and use an ir viewer to
see the fluorescent images, and adjust M5 to direct the images onto the
card.
You should see a cross-shaped figure centered in a circular background
fluorescence. The fluorescence is created by the scattered
light through the AOM and output coupler.
14. Remove Mi and replace it with the MI 0 for ps operation.
Mlo is held in place by a screw-in holder. Unscrew the holder and the
mirror will come out with it. The optic is retained by a small O-ring
and may be removed by simply pulling it straight out of the holder.
The optic has a v-shaped arrow on its barrel. This arrow points to the
coated surface that faces intracavity.
a. Reach in from both sides of the Mi 0 mount and unscrew the
knurled mirror holder of the output coupler (Figure 6-12).
b. Wearing clean finger cots or gloves, grab the mirror by its barrel
and remove it from its holder.
c. Clean the output side of the appropriate Mlo as described in
"Maintenance: General Procedures for Cleaning Optics" in
chapter 9, using the "drop and drag" method.
d. Install the optic in its holder.
The optic has a v-shaped arrow on its barrel which points to the
coated surface that faces intracavity. Press it in until the O-ring
captures it. Do not press on its optical surjace.
e. Clean the intracavity side in the same manner.
f. Screw the mirror holder into its mount.
Finger tight is sufficient; excessive force will damage the optic.