ENERGY DETECTORS
Gentec Electro Optics provides a full
range of products to meet your pulse
energy measurement needs. They range
from the tiny and sensitive QE4, the
lean and portable QE12 and QE25 series,
the large aperture QE50 series to our
large world class custom calorimeters.
Having introduced the first pyroelectric
joulemeter over 30 years ago Gentec-EO
is well established as an experienced
source of energy measurement expertise.
Be it in the laboratory or an OEM appli-
cation Gentec-EO will have a solution.
MONITORS ENERGYDETECTORS
How They Work
In the simplest terms, a pulse of light is
absorbed by the surface of the detector
and heats it up. That in turn, changes
the temperature in a pyroelectric mate-
rial underneath. This separates electri-
cal charges in the pyroelectric which
creates a voltage as the pulse of heat
energy passes through it to a heat sink.
The heat sink removes the heat energy
to allow the pyroelectric to be ready for
another pulse and to prevent it from
over heating. The electrical voltage read
by the measuring instrument is propor-tional to the energy. Figure 1 sketchesout
the basic structure of a pyroelectric
joulemeter.
POWERDETECTORS OEMDETECTORS
QE25-LP-H-MB
The Absorber
The business end of the detector is the
absorber that coats the side of the pyro-
electric that is exposed to the laser.
That material absorbs most of the light
energy from the laser and converts it to
heat. A small fraction is reflected. How
much is shown by the spectral response
curve for the material. The thermal mass
of the absorber and its thickness deter-
mine how quickly the heat can flow to
the pyroelectric detector and hence its
response time. Lowering the thermal
impedance by using an absorber with a
lower thermal mass or reducing the
thickness of the absorber will increase
its speed. The metallic MT coating is a
good example. It allows for a measure-
ment of each pulse up to 4000-6000 Hz.
QE4-SP-S-BL
QE50-LP-S-MB
PHOTODETECTORS ENERGYDETECTORS
Overview
DIFFRACTIVEOPTICS BEAMDIAGNOSTICS
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