Beam injector module, C-BI
This module allows a visible red laser beam to be aligned with the invisible infrared beam. This serves to
act as an alignment aid further down the beam and as a reminder that the infrared beam is also present.
+6V (& 30mA) is required at the jack connector to switch the laser on and light the LED indicator on the
side. The power supply supplied for this purpose is voltage switchable and polarity reversible. PLEASE
READ THE INSTRUCTIONS PROVIDED. IN PARTICULAR, THE WRONG POLARITY WILL
DAMAGE THE LASER. IF IN DOUBT, CHECK THAT THE TIP OF THE 2.5MM JACK HAS THE +6V
Inside the C-BI is a visible (red, 650nm) laser of 0.8mW power. As is usual for this type of device DO
NOT STARE INTO THE BEAM DIRECTLY AND ENSURE THAT YOUR EYES AVOID ANY
CO2 Laser Beam
This is to be directed into the input aperture. Make sure the beam is aligned to the centre of the beam
pipe before installing the C-BI.
The CO2 beam will pass through the ZnSe beam combining optic and emerge at the output aperture
together with the visible laser beam. Note that the clear aperture of this unit is 14.5mm.
IF YOU SEND THE CO2 LASER BEAM INTO THE WRONG APERTURE, A SMALL % OF THE
POWER IS REFLECTED UP TO THE DIODE LASER AND IT’S COLLIMATING LENS. DEPENDING
ON THE POWERS INVOLVED, THIS COULD DAMAGE THE DIODE LASER.
Alignment of Visible Beam
Before coupling to the beam pipe stick a piece of masking tape over the output aperture to check that
the beam is more or less central.
Turn the CO2 beam off. Mount the C-BI in the system and install a target or cross-wire further down the
Use an Allen key to adjust the tip and tilt screws A and B until the visible beam is central. Do not press
down on these screws otherwise you will compress the springs that you are trying to adjust.
Look for a clean beam. Any spurious flares or arcs will indicate that the tilt is so far out that the beam is
reflecting off the inside of the beam pipe.
Next either remove the C-BI or retract the beam pipe at the output side. Again place a piece of masking
tape over the aperture. Adjust the two screws X and Y to centralise the beam. There is a few mm of
movement available and the total area covered is circular.
When X and Y come loose while unscrewing or go tight while screwing in, the laser mount inside has
reached the limit.
The alignment process is iterative; adjust A and B to centralise the beam in the ‘far field’ and adjust X
and Y for the ‘near field’.
Finally, you may wish to make some fine adjustments with the CO2 beam on.