Spectra-Physics Tsunami - Selecting Wavelength, Fs Configuration (Using the Slit)

Operation
7-5
If you are using cables other than those shipped with the system, or if
you converted the laser from a ps to a fs configuration, or vice versa, or
if you changed optics sets, the phase signal may have moved outside
the range of the fine PHASE control. If this seems to be the case, refer
to the section, “Coarse Phase Adjustment...,” at the end of Chapter 6
for instructions on locating and changing the setting of the coarse con-
trol.
6. Adjust the dispersion control to optimize the pulse.
Adjust the prism dispersion compensation control (fs configuration) or
GTI POSITION dispersion control (ps configuration) until a short pulse
appears.
7. Vary pump power to optimize power and pulse stability.
8. Repeat Steps 5 through 7 until the Tsunami pulse is optimized.
9. Perform the test for proper modelocking. Refer to Chapter 6, “Align-
ment: Test for Proper Modelocking.”
This completes the system start-up and mode-locking procedures.
Selecting Wavelength, fs Configuration
(Using the Slit)
Use an IR viewer, beam splitter, suitable attenuator, and a monochromator
as described in Appendix B to monitor the Tsunami laser as you perform
the following procedure.
1. Using the IR viewer, beam splitter, and attenuator, pick off a portion of
the Tsunami output beam, attenuate it, and center it on the input slit of
the monochromator.
2. Set the monochromator wavelength to the desired laser operating
wavelength.
3. Using the Tsunami slit wavelength selector, tune the laser until the IR
viewer detects light exiting the monochromator, then optimize the out-
put from the monochromator.
4. Adjust the prism dispersion compensation control for the desired pulse
width.
Turn the prism dispersion compensation control micrometer in the
same direction as the slit wavelength selector to selected the wave-
length.
5. When you change to a wavelength that requires a different optics set,
you may have to change and realign the photodiode pc board. Refer to
“Aligning the Photodiode PC Board” in Chapter 6.
6. Set the optimum slit width using the slit bandwidth selector (shown in
Figure 7-2).
7. Optimize pulse width by adjusting the pump power and prism disper-
sion compensation control.
Iterate between adjusting pump power and the prism dispersion com-
pensation control to obtain the desired pulse width. The process will
merge to a point where the shortest pulse width at highest output