Measuring Repeating Pulses Of High Energy; Energy Log - OPHIR vega User Manual

6.5 Measuring Repeating Pulses of High Energy

Because of their construction, pyroelectric sensors are
restricted in the energy density they can withstand,
particularly for short pulses on the order of nanoseconds.
If the energy density of your laser exceeds the rating of
the pyroelectric absorber, there are several options
available:
1. You can enlarge your laser beam using a negative
lens until the energy density is below damage
threshold. You should test this using the test slide.
See section 4.6.
2. You can use a beam splitter, splitting off typically 8 -
10% of the light. If you use this method, note that
there may be polarization effects. You can calibrate
the beam splitter by running the laser at energy below
damage threshold and measuring the energy with and
without the beam splitter and you can then use the
attenuation feature (Section 4.6.1) to display the
actual laser power or energy.
3. Ophir has three sensors specifically designed for high
energy density pulses. They are the PE50HD sensors
with high damage threshold, the PE50-DIF model
pyroelectric sensors with a diffuser and the RP
thermal/photodiode sensors. Some of these sensors
can measure energy densities up to several
Joules/cm².
Contact your Ophir dealer for details

6.6 Energy Log

This is the same as for thermal sensors, except you do
not have to wait for "READY". See sections 4.5.6 and
4.4.2.6.1
Note:
For Pyroelectric sensors logging energy the only
setup option is 'sample rate'. The user can choose the
number of pulses he wishes to log - from 'every pulse'
to '1 out of 1000' pulses - but not the time period.
81
.