6
ISOMET
3.6
Locate the PWR ADJ access on the driver end plate.
3.7
With an insulated alignment tool or screwdriver rotate the PWR ADJ potentiometer fully anti-
clockwise (CCW), then clockwise (CW) approx’ 1/4 turn.
3.8
Connect pin 8 of the D-type to the modulation signal source and pin 9 to the (0V) return.
Apply a constant ON modulation signal:
- Standard and Option -A models, the modulation
is analog
(A-mod): ON = 10V.
- For Option -D models, the modulation is digital (D-mod): ON = High = 5V.
3.9
Apply a constant TTL high level to the digital gate input on the D-type connector.
Connect pin 6 to the signal source and pin 7 to the (0V) return.
Alternatively connect to a 5V DC supply if not actively used.
(This input is not required for -A or -D variants)
3.10
Apply DC power to the driver.
Input the laser beam toward the centre of either aperture of the AOM. Ensure the polarization is
correct for the AO crystal type and the beam height does not exceed the active aperture height of the
AOM. Refer to Figures 4,5,6, and appendix-A for beam alignment.
Start with the laser beam normal to the input optical face of the AOM and very slowly rotate the AOM
(either direction).
3.11
Observe the diffracted first-order output from the acousto-optic modulator and the undeflected
zeroth order beam. Adjust the Bragg angle (rotate the modulator) to maximise first order
beam intensity.
3.12
After Bragg angle has been optimized, slowly increase the RF power (rotate PWR ADJ CW)
until maximum first order intensity is obtained.
3.13
The driver is now ready for use. Figures 3 and 4 illustrate typical modulation characteristics.
* Standard values. Check specific model test data sheet