Calibration Of Pyroelectric Type Sensors - OPHIR vega User Manual

9.3 Calibration of Pyroelectric type Sensors

9.3.1. Two main types of absorber surface are used in
Ophir pyroelectric measuring sensors
1. Metallic Type: The type with no suffix in the name
have a partially reflective multilayer metallic coating
which absorbs approximately 50% and whose
absorption graph is shown in Graph 3 below. The
metallic coating permits very high repetition rates, up
to 25,000Hz as well as relatively high damage
threshold.
2. BF Type: The type with the BF suffix has a broadband
absorbing coating to provide high absorptivity from
the UV through the IR. This coating can withstand
energy densities, up to 0.8J/cm² for short pulses and
2J/cm² for long pulses without changing calibration.
The absorption of this coating is above 90% for most
of its range, as shown in Graph 3 below. This coating
is available for the PE50, PE25, and PE10 sensors. For
even higher damage thresholds, there are the – DIF
diffuser series with a diffuser in front of the absorber.
3. PD10 Series: Unlike the other sensors, the PD10
series sensors have a silicon or germanium
photodiode with a neutral density filter mounted
permanently in front of it. The filter detector
combinations are calibrated over the entire
wavelength range similarly to the PD300 power
sensors and therefore the sensors have a high
accuracy at any wavelength in the range. This is an
exclusive feature with Ophir energy sensors.
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