I was doing some rough alignment on my dual 445 module and noticed something that caught my interest.
I have ML7 safety glass that are designed to block specific wavelengths. The have OD ratings for 400nm, 532nm, red, and infrared. I have used them for blu-ray and they work very well, but the are def not designed for 445nm.
The 445 diodes I'm using were bin sorted high efficiency diodes from Krazer and I had them running at about 150mW while aligning the cylinder lenses. When I put on the glasses one of the beams almost completely disappears.
I assume that the glasses partially block wavelengths a bit higher than the 400nm that they are rated for. So one diode must be a higher wavelength that doesn't get blocked like the other diode. To the naked eye there is not really any difference in color but one beam does look brighter.
At first I wasn't happy that the two diodes were so different but I guess it doesn't really matter since its hard to notice. Maybe it will will be a good combo to use two slightly diff shades of blue.
Heres pics:
This is the two beams:
The is the same two beams but with the ML7 glasses used as a filter, the beam that is filtered out is circled in red: