Spectra-Physics Tsunami - Operating in the Broad Fs Regime (150 Fs - 1 Ps); Tsunami System Verification; Conversion for Broad Femtosecond Operation

Operation
7-7
Operating in the Broad fs Regime
(150 fs – 1 ps)
The Tsunami laser is capable of providing pulses in the range of 150 fs to 1
ps by using a combination of special
GTIs and the prism sequence used for
dispersion compensation.
Tsunami System Verification
Verify the following before you start the conversion process for broad fs
pulses:
1. Verify the coarse and fine PHASE settings on the Model 3955 are cor-
rect.
Refer to Chapter 6, “Alignment: Coarse Phase Adjustment...,” for
information on setting the coarse and fine PHASE controls.
2. Verify the beam is centered on the M
10
and that output power is opti-
mized.
If the beam is not centered on M
10
, refer to “Optimizing Laser Output”
earlier in this chapter to “walk the beam” and recenter it on M
1
and the
M
10.
Conversion for Broad Femtosecond Operation
1. Replace the M
1
HR with the appropriate GTI.
Refer to Chapter 5, “Installation: Installing the GTI.”
2. Place a white card in front of M
5
and adjust the GTI vertical and hori-
zontal controls to overlap the two fluorescent images from M
1
and M
3
on the card so they form a cross. Once overlapped, the laser should
lase when you remove the card.
3. Adjust the GTI vertical and horizontal controls to optimize output
power.
4. Select the desired wavelength using the slit wavelength selector.
Figure 7-4: Placement of Pr
1
and Pr
4
in beam
5. Move prisms
Pr
1
and Pr
4
so that the beam passes through them about 2
mm from their apices (Figure 7-4). For x-long wavelengths, ensure the
beam is not clipped by these prisms.
Access holes through the beam protection plates provide access to the
prism adjustment screws.
2 mm (0.08 in.)
Beam
Prism