We’d all like to imagine that our things will stay in mint condition forever. But we know that’s not the case. Just like laser degrade (and therefore must be measured), the measurement equipment itself will slowly drift away from its precise calibration.
This is why we recommend yearly calibration. If you aren’t sure when your laser power or energy is due for recalibration, you can check by connecting it to a meter. If it needs to be recalibrated, a notification will pop up on the first screen.
Here’s how the recalibration process works.
Measuring the power of scanning lasers such as barcode scanners presents a problem. A bar code laser beam scans back and forth at a very high frequency so an ordinary photodiode power meter will not measure the power in the beam but rather the average power impinging on it, i.e. the power times the fraction of time the beam is on the detector. Therefore, when exposed to a scanned beam, the reading will be much lower than the actual power in the beam. For example, if a scanning laser delivers 2mW to a photodiode sensor and the beam is on the sensor only 1% of the time, the instrument will read only 0.02 mW.
Updated March 2016: I made a few changes to this post now that the new low power RM9-PD is available.
There are many different types of lasers.
UV, visible, infrared, Terahertz.
Nanowatts, milliwatts, kilowatts.
Lasers for industry, laser for medicine, lasers for telecommunication.
The 3A family of laser power sensors is one of our most popular – and for good reason.
You might already know the basic points:
It’s very sensitive (down to 10 μW), yet comes with all the benefits of a thermal-based sensor: high damage threshold and spectrally flat across a very wide spectral range.
There are a few different ways to measures laser power, but the most common is the photodiode. Photodiodes translate light energy into electricity (current), which can be measured by a current sensor.
Ophir uses a few types of photodiodes in its PD300 series.