Chapter III –Subassemblies
3-11
C
996-0255 rev. b
750 volt power board:
This board, located under the laser bench, generates the dc voltage neces-
sary to power the Marx board. The DC voltage is adjustable by a pot
accessible through a hole in the top of the laser bench. Turning the pot
clockwise raises the voltage.
Cavity closed:
The beam propagating within the oscillator cavity makes a double pass
through the Pockels cell and quarter-wave plate. At 0 volts on the
Pockels cell (PC) it adds no rotation while the quarter-wave adds 45° with
each pass, giving a total rotation of 90°. Thus the horizontal beam that
transmitted through the plate polarizer is rotated to vertical and is re-
jected by the polarizer and no oscillation occurs.
Cavity open:
The beam propagating within the oscillator cavity makes a double pass
through the Pockels cell and quarter-wave plate. At 3600 volts on the PC
it adds 45° rotation and the quarter-wave adds 45° with each pass, giving
a total rotation of 180°. Thus the horizontal beam that transmitted
through the plate polarizer is rotated to vertical and back to horizontal so
that it is transmitted by the polarizer allowing oscillation to occur.
Polarization:
horizontal = H
vertical = V
circular = C
rejected vertical
output
mirror
laser head
polarizer
CC
CC
HR
mirror
PC ¼
plate
V
V
HH
0 Volts
Cavity closed – no lasing.
output
mirror
laser head
polarizer
V
C
V
C
HR
mirror
PC
¼
plate
H
H
3600V
Cavity open and lasing.
H
H
laser
pulse
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