Tsunami - Beckman Institute Laser Resource Center

Operation
Operating with the Ultrashort Pulse Option (USP)
The USP option allows operation of the Tsunami laser in the standard
wavelength region (720 - 850 nm) with < 50 fs output pulses. The basic
operation of the USP option with regard to pump power, Pr2/Pr3 adjustment,
slit width adjustment, etc., is identical to laser operation in the
standard fs regime. However, the USP option uses prisms with a lower
refractive index which requires less glass to be inserted into the beam in
order to produce short output pulses.
Operating in the Broad Femtosecond Regime
(150fs-1 PS)
Tsunami System Verification
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.
Verify the following before you start the conversion process for broad fs
pulses:
1. Verify that the coarse and fine PHASE settings on the Model 3955 are
correct.
Refer to chapter 6, "Alignment: Coarse Phase Adjustment ...," for
information on setting the coarse and fine PHASE controls.
2. Venfy the beam is centered on the Mlo and that output power is
optimized.
Conversion for Broad Femtosecond Operation
If the beam is not centered on Mlo, refer to "Optimizing Laser
Output'' earlier in this chapter to "walk the beam" and recenter it on
MI and the Mlo.
1. Replace the M1 HR with the appropriate GTI.
Refer to chapter 5, "Installation: Installing the GTI."
2. Place a white card in front of M5 and adjust the GTI vertical and
horizontal controls to overlap the two fluorescent images from M1 and
M3 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.