Didn't know you have a 7W unit but if this 7W is from Jet Lasers and performing fine I would bet it does 7W+ as they are usually over spec.
There you go on Bowties link. What didn't you find, the link or meter?
I'm not sure if member "Hakzaw" still has the Hyperion meters for sale which might be a option.
You said in the OP "I have seen videos on YouTube where ppl blast black balloons from 15feet away using a 2W laser pointer".
Is important for you to understand/know/recognize that a laser beam has no temperature - there is no inherent "temperature" to a laser beam. Heat is the random motion of matter particles (atomic or molecular particles).
A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature.
"Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy.
"Burning" depends upon the ability of the target to absorb and convert the light energy of whatever wavelength to heat.
The 980nm laser maybe be perfectly fine --could be the pigments in your "black" balloon do not absorb 980nm well or at all.
JetLasers is pretty good about allowing returns for full refund if you don't like or can't use whatever laser you bought from them.
So, if your bought the 980nm laser imagining it would pop balloons or "burn" things like a 2.5W blue laser or any other wavelength would, that is not how lasers work on the real world.
You can return any JetLasers product, generally, if it is in as received new condition. Ask JetLasers via email.
You can read about return details here: https://www.jetlasers.org/index.php?id_cms=1&controller=cms
well..... get a 60/40 mirror, if you can find one with specifications for 450 nm, and then reflect 60% of the power away from the sensor, then calculate the real power. I don't know, would that be 60/40 or 40/60 guys? I suppose the angle would be critical or your readings would be off.
He can either use a neutral density filter or a variable beam splitter to get a fraction of his 7 watt 445nm laser to a lower power LPM to get an accurate measure of its power. You can also buy beam splitters that are set to a fractional distribution.