LUMENIS VersaPulse PowerSuite - Page 40

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FIG. 3.7
Make a slight adjustment to the second relay mirror, then check the result by making a burn
on photopaper at the second wedge optic. Because a number of burns may be required to
complete the adjustment, using the test aperture can slow things down (the aperture would
have to be reloaded with a clean piece of paper after each shot). As an alternative, find a sec-
ond channel that is already centered in the aperture, and then use the service screen to turn
that channel on as well as the channel to be adjusted. When the laser is fired the two channels
will each fire in turn. Instead of using the aperture, make the burns on a larger piece of paper
held in front of the aperture, moving to a clean spot for each check. The known good channel
becomes the reference - adjust the second relay mirror for the channel out of adjustment until
the burn footprints are on top of each other. Once the channel is roughly positioned over the
aperture, lock down the mirror and go to step "c" below.
c. Set the system to the following repetition rate and align the YAG beam into the fiber port using the
Fiber Alignment Detector Box (Transimpedance Amp).
Holmium: Repetition rate = 40 Hz
Nd:YAG: Repetition rate = 60 Hz
Insert the service attenuator into the beam path (SW4 on the CPU PCB to the left). Connect the
fiber alignment detector box to the fiber port and oscilloscope. Select the proper repetition
rate according to the type of system being worked on. Then adjust as indicated in the sub-
paragraph below.
Fire the laser while observing the oscilloscope. Each laser pulse will produce a squar-
ish pulse on the screen. Make slight adjustments to the channel first relay mirror to
peak the amplitude of the pulses on the oscilloscope. Use the highest scope gain and
adjust for the highest peak.
B
eam is clipping the
1
0mm burn aperature
t
ool. Adjust plano
r
elay mirror down and
t
o the right to center
t
he burn.
An oblong or small
burn spot or distorted
burn spots usually
indicates that the cavity
is not peaked or some
of the cavity optics are
damaged. Check HR, OC,
and rod for burn spots.
The burn is round
and centered in the
aperature. The goal
is to get all four channels
centered, at the same
time each beam is
centered (peak signal) on
the transimpedance
detector.
All four burns are
centered. The overall
diameter of the burn i
s
slightly larger than an
y
one single burn.
This is OK.