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 Laser power measurements should be quick and easy. They should
not involve time consuming set-up and alignment problems. Ideally, the measurements
should also be able to be made at any point in an optical system where losses are
likely to occur.
Unfortunately, most laser power meters have sacrificed ease of use to gain continuous
power readings. However, in most laboratory and production situations, the usual
requirement is for a quick spot-check of power with a minimum of disruption. Even
when tuning up a laser, researchers have found that it is best to tune for a desirable
mode pattern using Thermal Image Plates*, then briefly check the laser power.
The Power Probes are calorimeter-type power meters which measure laser power using
a timed exposure. They display average power absorbed on a calibrated readout scale
and can be used with continuous or repetitively pulsed lasers ranging from small
2 watt YAG lasers to large 10,000 watt CO2 lasers.
*Thermal Image Plates and Beam Probes are viewing devices for CO2,
CO, HF, and YAG lasers. Data sheets are available from Macken Instruments, Inc.
Select Features
- The absorbing head of a Power Probe is conveniently sized. An absorbing head
is large enough to be easily used, yet small enough to be inserted between optical
components to measure the laser power without disturbing set-up.
- The hand-held meter requires only about one minute to make a power measurement.
- The absorbent coating is very tough, resisting mechanical abrasion and water
immersion.
- A zero adjustment mechanism has been incorporated into the design to expedite
and simplify the power measurement process.
- An accurate and durable all-metal construction has been used to insure a long
life.
Taking Measurements
Each Power Probe is a self-contained unit consisting of an absorbing head, a temperature
measuring mechanism, a zeroing knob and a readout dial. In operation, the dial is
zeroed. Then the absorbing head on the end of the Power Probe is exposed to the laser
beam for a specified time interval. After the Power Probe has been removed from the
laser beam, the average laser power can be read out on the dial. The process takes
about one minute. If it is necessary to make several power measurements in succession,
the absorbing head can be rapidly cooled by immersing in a beaker of water between
measurements.
The Laser Power Probes have proven to be so popular that Macken Instruments now offers
13 flat and 2 conical models. The models include 8 different power ranges and 2 different
absorbing coatings.
- The "Y" series Power Probes have a broad spectral absorption
coating which can be used from 0.2 to 11u. These Power Probes are designed for use
with the YAG or CO2 lasers.
- The "C" series Power Probe can only be used with CO2 laser wavelengths.
The "C" series is recommended for use with CO2 lasers because the
coating generally has a higher damage limit than the "Y" series.
For CO2 lasers in excess of 1200 watts, there are two additional power probes available
based on conical absorbing heads. These conical heads exhibit a higher damage threshold
than the standard flat surface heads. However, the conical head power probes are
thicker and have a smaller target area than the standard flat probe of equivalent
power ranges. See the Conical Power Probe data sheet for more information.
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