Energy, Power Or Exposure Measurement - OPHIR vega User Manual

6.4 Energy, Power or Exposure Measurement

Warning:
Before using the sensor for power or energy
measurement, check that your laser energy, energy
density and average power do not exceed the sensor
ratings as listed in the table with the sensor
specifications at the end of the manual, otherwise,
there is a risk of damaging the absorber. 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 shows
damage, then either enlarge your beam or lower the
laser energy until damage is no longer seen.
Note:
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.
6.4.1. Energy Average Power and Frequency
Measurement
Unlike most pyroelectric energy meters, the Vega
measures the pulse frequency to a high degree of
accuracy and is therefore able to display pulse frequency
and average power as well as pulse energy. The
following paragraph will describe how to set up and
measure these functions.
6.4.1.1. Zeroing Sensor against the Vega Meter
There is a slight variation of pyroelectric reading from
meter to meter. Therefore, for the most accuracy in
pyroelectric energy measurements, it is necessary to zero
the pyroelectric sensor against the Vega display it will be
used with. After this is done, the sensor is "conditioned"
to work with the particular Vega the zeroing was done
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