Spectra-Physics Tsunami - Opto-Mechanical Controls All Systems

Tsunami Mode-Locked Ti:sapphire Laser
4-4
Opto-Mechanical Controls
All systems
The following is a description of the opto-mechanical controls common to
fs- and ps-configured systems. Refer to Figure 4-3 and Figure 4-4.
P
1
pump beam steering mirror—directs the input pump beam onto the
center of pump beam focus mirror P
2
. It has vertical and horizontal adjust-
ments.
P
2
pump beam focus mirror—directs the pump beam through the cavity
focus mirror M
3
and focuses the pump beam into the Ti:sapphire rod. It has
vertical and horizontal adjustments, and it sits on a dovetail slide so that its
distance from the Ti:sapphire rod can be adjusted. A setscrew on the edge
of the slide holds it in place. The mirror is translated with respect to the rod
to create a uniform focused spot size in the rod and to compensate for the
difference in beam divergence among different pump lasers.
M
2
and M
3
cavity focus mirrors—center and focus the cavity beam waist
in the Ti:sapphire rod. They have vertical and horizontal adjustments, and
their distances from the rod are adjustable: M
2
has a micrometer adjustment.
M
3
has a dovetail slide that is held in place with a setscrew (Figure 6-3).
M
4
and M
5
cavity fold mirrors—fold the beam and allow for a compact
laser. M
4
directs the cavity beam to M
5
, and M
5
directs it either to the AOM
(ps configuration) or Pr
1
(fs configuration). In the Lok-to-Clock version, the
M
4
contains the PZT for cavity length stabilization and has a short cable and
connector for plugging into the driver cable near it in the tray. Both mirrors
have vertical and horizontal adjustments.
AOM—is driven by the Model 3955 electronics module to insure proper
pulsing at start-up and, when the optional Model 3930 Lok-to-Clock mod-
ule is present, assists in synchronizing Tsunami pulses to another source.
The
AOM has pitch and Bragg-angle controls.
M
10
output coupler (OC)—one of two cavity end mirrors. Whereas the
high reflector reflects all light back into the cavity, the output coupler
allows a small percentage to pass through as the output beam. Its vertical
and horizontal adjustments allow you to align the laser cavity and to opti-
mize output power and mode quality. These controls are accessible when
the laser head cover is in place.
Rod translation control—vertically translates the Ti:sapphire rod in a
plane parallel to the face of the rod. Use it to maximize output power dur-
ing alignment. The dovetail slide is held in place with two screws (refer to
Figure 6-4).
The mirror control knobs are color-coded for easy identification: blue
for vertical, green for horizontal.
Caution!