Tsunami - Beckman Institute Laser Resource Center

Tsunami
Selecting, Installing, and Aligning
the Birefringent Filter (ps Systems Only)
There are two birefiingent filter (bi-fi) sets that cover the Tsunami ps wavelength
range. The "A" plate bi-fi has a yellow dot on the filter ring, the "B"
plate bi-fi has a white dot. Use the "A" plate with the blue, standard, long,
or extra-long optic sets. Use the "B" plate with the midrange optic set.
CAUTION
The alignment of each filter stack is set at the factory and does not require
adjustment. Never try to disassemble the stack.
Once you have chosen a wavelength at which to operate, select a filter and
follow the procedure below to install and align it. Use Table 6-2 to select
your filter.
A monochromator is required for this procedure.
1. Close the pump laser shutter.
2. Set the bi-fi micrometer to it maximum clockwise position.
3. Install the appropriate filter in the holder.
a. Place the filter in the holder.
b. Rotate the filter until the pair of setscrew holes on the outer edge
of its ring (Figure 6-3) is near the position listed in Table 6-2 for
your wavelength. Note: the "12 o'clock" position is the highest
point and is nearest you as seen from the output bezel. This gets
you close.
c. Open the pump laser shutter.
d. While watching the monochromator throughput from the
Tsunami, rotate the filter slightly by hand until you obtain the
lower wavelength listed in Table 6-2.
e. Close the pump laser shutter.
Table 6-2: Bi-Fi Alignment for the Nominal 2 ps Systems
Optic Set
Plate Type1
Dot Color
Setscrew
Position (o'clock)
Lowest
Wavelength
Highest
Wavelength
*
Blue (8)
Standard (S)
ANellow
ANellow
1 :00 to 2:00
12:OO to 1 :00
688 nm
715 nm
790 nm
850 nm
Mid-range (M)
BANhite
1 :00 to 2:00
775 nm
900 nm
Long (L)
X-long (X)
ANellow
ANellow
1 :00 to 2:00
12:OO
835 nm
965 nm
1000 nm
1080 nm