1919-R User Manual
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7
Pyroelectric and Photodiode Energy Sensors
1919-R supports the new 919E series of sensors. Older energy sensors are not compatible.
For a list of all the available Pyroelectric and Photodiode Energy Sensor models that can be used
with 1919-R, see
Warning:
Before using the energy sensor for power or energy measurement, check that your laser
power, energy, and energy density do not exceed the sensor ratings. See
Topics include:
Pyroelectric Sensors – Method of Operation
Photodiode Energy Sensors – Method of Operation
Measuring Pulses of High Energy Density
Operation of 1919-R with Pyroelectric and Photodiode Energy Sensors
7.1
Pyroelectric Sensors – Method of Operation
When a pulsed heat source, such as a laser, is directed at the detector sensor, a temperature
gradient is created across the Pyroelectric crystal mounted in the sensor. An electric charge is
produced which is proportional to the energy absorbed. The detector sensor has sophisticated
circuitry unique to Newport (patented) that determines the baseline before the pulse is received,
measures the voltage after a predetermined interval, amplifies it and holds it for a predetermined
time.
Due to this innovative circuitry, Newport Pyroelectric sensors can measure very long pulses as well
as short ones. They can measure low energies as well as high. They can also measure at higher
repetition rates than was possible before.
The 1919-R meter amplifies this signal and indicates the energy received by the sensor as well as
the frequency at which the laser is pulsing. Using the energy and frequency information, 1919-R is
also able to display average power.
7.2
Photodiode Energy Sensors – Method of Operation
The 919E-20U-10-20K operates in a similar fashion to the Pyroelectric-based sensors except it has
a Photodiode detector instead of Pyroelectric. Because of its great sensitivity, it can operate down
to about 1nJ of energy. It has complete wavelength correction over its entire measurement range
of 200 - 1100nm.
