LPM Mods Moved from Sales Thread.....

[lasersbee]

Question for you -

If I want to meter above 2.5W with this LPM, is there any way to do this with filters?

IE, are there (affordable) filters that are consistent and predictable enough to provide some sort of linear (or at least calculable) reduction in beam intensity? Such that if I wanted to test a 7W laser, I could shine it through XYZ filter, and the filter would always be passing some calculable portion of the light to the sensor, etc. ?

Follow-up question:

- If it's not possible to actually get a predictable filter and do as in my post above, what about the following. Most important for my application is the ability to detect a plateau in the mW curve. So for that, I mostly need to watch relative change in power, but the numbers themselves don't have to mean anything.

- So what if I took a white TEC (I have one), soldered it to a 1/8" jack like the LPM uses (I have one of those too), and then unplugged the stock sensor, and used the make-shift one I rigged up. For one, a white TEC wouldn't absorb nearly as much heat, but it would absorb enough to get a reading, especially at high powers. Second, the calibration wouldn't matter, since it would just be relative power I'd want to detect.

I guess my biggest concern here would be - does this risk throwing off the LPM's internals? I can't see how, but I also don't know what I'm talking about when it comes to the LPM's internals

As I have already posted many times about increasing the range
of our HLPM II optical LPM Module... you can use a standard Glass
ND filter to be able to read higher powered lasers...

That is the same for Thermopile Sensors.. In both cases the ND
filters must be tested/calibrated to the Wavelength of the Laser
being used.
We have found that the same cheap ND filter does not reduce the
Laser energy the same at different wavelengths...

To answer your question... Yes... Use a Glass ND filter that
you Test/Calibrate to your Laser's wavelength...

BTW... if you plug any other device into a Laserbee Sensor jack
there are 2 things to remember....

1) the Sensor supplied with a LaserBee is calibrated to that
specific LaserBee and is recorded based on the Serial Number.

2) any other device will NOT be calibrated to that LaserBee
We compensate for the LaserBee Thermopile coating non linear
output in Firmware... a non coated TEC will not have the same
output curve...

3) any other device plugged into the LaserBee will void any
guarantee and may damage the LaserBee.


Jerry

 

[Meatball]

Assuming the incident beam is unpolarized, couldn't one just put a polarizer over the sensor? This should consistently allow half of the beam's intensity through. This would double your power reading capacity.

 

[rhd]

We have found that the same cheap ND filter does not reduce the
Laser energy the same at different wavelengths...

To answer your question... Yes... Use a Glass ND filter that
you Test/Calibrate to your Laser's wavelength...

Ok so essentially -

1) Without any filter, LPM the target wavelength at a power within the LPM's working range.

2) Then LPM the same laser with the ND filter inline with the beam.

3) The same ratio will then scale linearly to testing higher power outputs of the same wavelength?

 

[laser_freak]

Instead of using a ND filter, why not use a 50/50 beam splitter, or any other ratio splitter for that matter?

Assuming the incident beam is unpolarized, couldn't one just put a polarizer over the sensor? This should consistently allow half of the beam's intensity through. This would double your power reading capacity.

That assumption is rarely if ever true.

 

[lasersbee]

Ok so essentially -

1) Without any filter, LPM the target wavelength at a power within the LPM's working range.

2) Then LPM the same laser with the ND filter inline with the beam.

3) The same ratio will then scale linearly to testing higher power outputs of the same wavelength?

Exactly.....

Assuming the incident beam is unpolarized, couldn't one just put a polarizer over the sensor? This should consistently allow half of the beam's intensity through. This would double your power reading capacity.

I have no idea... We have never tried this over different Wavelengths
at a large range of powers...


Jerry