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*The
News* The
*News* about
these
devices is very good and getting better. Vigo has changed
over production to new MOCVD equipment, which gives much better
control of material properties and device architecture. This
has lead to a rapid escalation of device sensitivity. Now
we can readily deliver TE-cooled photovoltaic devices with D*(10.6
microns) > 2.5x10E9 cm.hz1/2W-1 from DC to >80 MHz and TE-cooled
photoconductive devices with D*(12 microns) > 3x10E9 from >20
kHz to >15 Mhz. These device operate entirely without LN2
or any other cryogenics yet provide performance that is only a factor
of 3 to 5 less than cryogenic devices, and 10 to 1000 times better
than other non-cryogenic detectors!
How
do they do it? CLICK HERE for a brief presentation on the technology
and progress this represents.
Our basic product line
features infrared detectors whose sensitive wavelength begins in
the visible or around 2 microns. The longest wavelength they
measure varies; models are available that measure to 3 microns,
4 microns, 5 microns, 6 microns, 8, 10.6+ microns, 12 and 13 microns.
These detectors are optimized to specific wavelengths, and are appropriate
for use over a spectral range beginning at 1 micron for photoconductive
types and at 2.5 microms for photovoltaic types and dropping off
fairly sharply beyond their optimized wavelength. Also available
are several CO2 laser detectors, which have optimum operation
at a nominal wavelength of 10.6 microns. For
a pdf covering most of our IR quantum detectors, click here-
or email, fax or phone with a postal address and we will mail the
info.
Photoconductive vs. Photovoltaic
The detectors come in
photoconductive and photovoltaic types. Photovoltaic detectors
create a measurable voltage and current in response to photon bombardment,
much like a solar cell. Photoconductive devices change resistance
when photons come in. A low noise bias current must be used
to measure the resistance change. Photoconductive devices
tend to have somewhat higher signal (responsivity) and sometimes
slightly better signal-to-noise than photovoltaic equivalents when
operated at optimum frequencies. On the other hand, photoconductors
exhibit excess noise at low frequencies - called 1/f or flicker
noise, are often slower in frequency response, and the low noise
bias circuit costs money. For these reasons, the photovoltaic
devices are preferred for most applications. Nevertheless,
photoconductors can be made with larger active areas than PV devices,
so sometimes the need for larger area will prevail over the other
advantages of PV devices and make PC the right choice.
Sensitivity
Sensitivity of our detectors
can be increased by thermoelectric (TE) cooling or by the use of
an immersion lens, or both. TE-cooled detectors must be mounted
on a heat sink. Additionally, a TE-cooler power supply/controller
is necessary.
Spectrum
View detectors for the
spectral regions below.
Choosing a detector and,
if necessary, an associated preamp and TE cooling device can be
a confusing task. The following summaries identify some of
the issues to be aware of.
The following articles
offer assistance in selecting a detector and in proper care and
wiring of the detector.
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*The
News* The
*News* here is about our June 2007 appoinment as exclusive agents
for North America for Heimann. Heimann is the
leading producer of thermopiles in the world. Their process
is totally based on silicon and specifically on silicon that can
be made by standard microcircuit processes, with resulting LOW COST
and HIGH SOPHISTICATION.
In general, our thermal detectors
are used for non-contact temperature measurement and for gas concentration
sensing by absorption of IR radiation at a specific wavelength in
a gas cell. We encourage your inquires - please tell us about
the details of of your application, quantities invloved and schedule
on which samples and production quantities will be needed.
We will respond with our suggestions regarding detector type (Thermopile
of Pyroelectric) and other details.
IR
Camera! Another very intersting Heimann Sensor product
is a LOW COST IR camera Model AXT100 using a thermopile array 32x32
element focal plane. For
detail click here.
Please watch this page for a more
complete description of the product line. Meanwhile, click
here for our version of the Heimann Sensor product
lit. Also please visit www.heimannsensor.com.
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