New Focus Vortex 6000 Series - Operating in Constant-Power Mode

26 • Constant-Power Mode NEW FOCUS, Inc.
Following are the specifications for the external components you will
need to supply:
Beamsplitter: An external beamsplitter is needed to sample the laser
output. The reflectivity of the beamsplitter at the Vortex wavelength
should be approximately 10%. The beamsplitter should also have a
constant reflectivity over the tuning range of the laser. A recommended
beam pick-off is the New Focus Model 5801 wedged Beam Pick-off.
Photodetector: An external photodetector is needed to measure the
power in the beam sampled by the beamsplitter. The detector gain
must be large enough to generate a signal of 4 V when the laser is
operating at its maximum output power. For example, with a full
output power of 10 mW, and a 10% beamsplitter, the detector
conversion gain must be 4000 V/W. Recommended detectors are the
New Focus 2001 and 2011, as they provide sufficient gain and the gain
is adjustable.
Operating in Constant-Power Mode
Setting up and Aligning the Laser
Before switching to constant-power mode, use the Vortex in constant-
current mode to set up and align the laser.
1. Turn on the Vortex keyswitch and allow the system 20 minutes to
warm up.
2. If the Constant Power indicator is on, press the Mode button to
switch the laser to constant-current mode.
3. Push the Power button to activate laser power.
4. Turn up the laser current to the recommended operating current,
as specified in the Acceptance Test Data Sheet.
5. Direct the output beam through the beamsplitter.
6. Direct the sample beam onto the photodetector: Use caution to
prevent back reflections into the laser.
7. Connect the photodetector output to the Auxiliary Input on the
back of the Vortex controller.
Vortex6000.book Page 26 Tuesday, February 19, 2002 3:25 PM
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