Pyroelectric and Photodiode Energy Sensors
StarBright User Manual
48
8.4.3
Energy, Average Power, or Exposure Measurement
With the Pyroelectric sensor, you have been supplied a test slide with the same coating as on your
Pyroelectric detector. You can also obtain this slide from your dealer. You should use this slide to
test the damage threshold with your laser pulses. If the slide is damaged, then either enlarge your
beam, or lower the laser energy until damage is no longer seen.
The Pyroelectric sensor is capable of measuring pulses up to very high repetition rates on the
order of kilohertz or higher. The StarBright meter will sample pulses at up to 25,000 pulses
depending on the sensor. However, the display can only display at rates up to 10Hz.
Note:
High-sensitivity Pyroelectric sensors (PE-9, PE-10) are very sensitive to vibration, and
therefore might read a false trigger when operating in an acoustically non-stable environment. Set
the threshold to a high enough value that false triggering does not occur. Ophir also offers a shock
absorbing mounting post (P/N 7Z08268) that helps reduce vibration on the sensor.
8.4.4
Measuring Laser Energy
To measure Pyroelectric energies properly, it is important that the sensor is not grounded to the
optical bench. Make sure that the sensor is isolated electrically from the ground. The PE sensor
has been supplied with an insulating mounting post for this purpose.
To measure laser energy:
1.
Set
Measuring
to
Energy
.
2.
Set measurement parameters as
“Energy” is displayed on the screen as well as the laser’s frequency, and the units are mJ, µJ,
and so on.
Figure
8-4 Pyroelectric Energy Needle with Persistence