- Aug 3, 2009
On both filters on Alibaba you can see:
700~1000nm Tmax. ≤2%, Tave<1%
This is an excellent block rate. Maxmum throughput for IR in this range is 2% at 808nm and 4% at 1064nm.
The lower light throughput at these wavelengths the better.
You can also see the following figures:
420~620 nm Tmin≥88%, Tave≥90%
This means that this IR filter will reduce your green output with about 10%. So if you measure 200mW output with the IR filter, you can be fairly confident that it performs around 222mW without IR filter.
Will one or two IR filter be enough for all my lasers?
Lets say you once again measure 200mW with an IR filter. That means in theory that it should output 222mW green without the IR filter.
To test this you put another IR filter in front of the first. Now you should see a drop from 200mW to 180mW. As the IR filter shaves off 10%. If you see a larger drop than this, lets say 200 -> 150mW, you know the IR filter also eats up 25% green 532nm.
So from these figures you can calculate that the laser performs 266mW green without the IR filter.
A IR filter for yellow will fit for green, red,or violet laser?
It is because of this you actually get the stray readings. A 100mW laser which leaks a lot of this "processing" light may only do 20mW of green. While another may do 80mW green. Both will read 100mW on the LPM.
This is why you want an IR filter for testing.
A fair assumption is around 15-30% worth of IR on the types of lasers you resell. The one I reviewed was about 50mW stable green, with 65mW inclusive IR. So about 23% IR.
Hope this clarifies some stuff!