Power Meters FAQ's

BeamTrack Power/Position/Size Sensors

06/09/14

The Vega, Nova II, StarLite. StarBright and Juno support the BeamTrack (PPS) sensors. All other instruments can display power and single-shot energy of a BeamTrack sensor, but do not display beam position and size.

06/09/14

Yes StarLab can log beam position. The BeamTrack sensors are thermal sensors. The power measurements for all Ophir power sensors are logged at 15 times a second. When a BeamTrack sensor is connected to StarLab via a Juno, the position / size measurements are also logged 15 times a second. When a BeamTrack sensor is connected to StarLab via a Vega/ Nova II, the position / size measurements are logged once a second. This is because in the Vega / Nova II we sample these parameters slower.

05/26/15

The Ophir BeamTrack series of Power/Position/Size meters may be just the thing. In addition to all the things an ordinary power/energy meter does, the BeamTrack will measure the beam position and size as well to a precision of ~0.1mm. For a gaussian beam it will give you the actual beam waist diameter and for other beams it will give a relative number that changes with beam size. See http://www.youtube.com/watch?v=U2oliO-Cz8M for a demo of the BeamTrack.

05/26/15

The specified response time is only for the power and not for the size or position; response time is intentionally given in the Power section of the spec.
We haven't defined a position and size measurement response time because it depends on too many different parameters. For example:

  • Small changes in size or position will respond quickly, large changes are much slower.
  • Going from a large spot size to a smaller one is faster than going the other way.
  • Position and size can change at the same time.
  • If the power also changes it is even more complicated.

So the response time for size and position cannot be meaningfully specified by a single number. Having said all that, however: 
In general, unlike the power reading which is accelerated by the predictive “speedup” function, the size and position measurements can't use the speedup so they are a bit slower.

The rise time for Position and Size is typically 5x – 10x the specified power response time.

Fall times for a decrease in power density (i.e. increase in size relative to power, as above) can be longer.