Power testing SD Laser 301 from Fasttech.com

Hello guys, I just had some time and decided to test the true power output of the SD Laser 301 I recently purchased from fastech. The laser is rated for <5mW. The test isn’t exactly up to scientific standards, but it will give a decent idea of the laser’s power output.

The equipment I was using:

  1. SD Laser 301

  2. Newport Corporation 835 Optical Power Meter
  3. Newport 2.0 OD, neutral density filter

Here is the lab setup:

I first started out with setting the detector wavelength to 530nm, and zeroing the power.

Since the detector itself is only rated up to 2mW, I had to reduce the laser output with the use of an ND filter. In this case, I chose a 2.0 filter which will reduce the beam power by 99% (1% transmittance). Since we know the output and the OD rating of the filter we can solve for the actual laser output.

The formula that I used to calculate the laser power is OD=-log10(I_in/I_out). Solving for I_out:
I_out = I_in/(10^-OD).

Here is the power at the meter:

So after calculating the power based on the power meter output I get I_out = 3.7mW

Once again, it’s not extremely accurate but I think it’s good enough to see that it’s within spec.
In the future I would like to get a few higher power lasers and perform similar experiments.
Thanks for reading.