Lowest divergence 445-480nm diode

[Albert1007xd]

Hey everyone,

As the title says, I'm looking for the blue diode (doesn't matter if violet blue, pure blue or green-ish blue) that has the lowest divergence out there. Lower than 1mrad if possible (I'm planning to build a pen-style one for pointing, and as some of you know, blue is my favourite color, I know that 520nm is brighter for pointing but I prefer sticking to blue).

The power would be just enough to clearly see the beam at night, there's no special need to burn the house down (0.1-0.5W more than enough).

I've seen the Osram PLT5 450B and the Osram PL450B as the most probable candidates by their overall specs. Which one has the cleanest and smallest dot at range?
I've also seen that the PLT5 increases noticeably the WL when increasing the mA. Wouldn't matter having 350mW of 465-470nm single mode :na:

Thank you everyone in advance!

 

[diachi]

The PL450B and the PLT5 450B use the same emitter, the only difference is the package. One is 3.8mm (PL450B) and the other is 5.6mm (PLt5 450B). Other than that they are the same diode.

Final divergence will depend on your choice of collimating lens. 3 element is probably the best choice, someone correct me if I'm wrong?

 

[Albert1007xd]

Thanks for your answer!
Was planning to use 3E lenses for having the best beam.

 

[diachi]

Thanks for your answer!
Was planning to use 3E lenses for having the best beam.

Divergence should be pretty good with that LD/lens combo. Not sure exactly what divergence you'd get though, someone else may have one they can test. My quick search didn't turn up any solid numbers.

 

[Albert1007xd]

Divergence should be pretty good with that LD/lens combo. Not sure exactly what divergence you'd get though, someone else may have one they can test. My quick search didn't turn up any solid numbers.

With that lens and that diode at, let's say, 300-350mW, the beam would be clearly visible at night?

 

[diachi]

With that lens and that diode at, let's say, 300-350mW, the beam would be clearly visible at night?

Yeah, definitely. Even at 100mW it'd be fairly visible.

 

[Albert1007xd]

Great, thanks! I've seen that the maximum current suggested to the PLT5 is 300-350mA, isn't it?

 

[diachi]

Great, thanks! I've seen that the maximum current suggested to the PLT5 is 300-350mA, isn't it?

Yeah, 300mA IIRC. Should do around 300mW at that current. Of course, there's the usual small variations from diode to diode and differences in choice of lens.

 

[BowtieGuy]

Hi Albert, I've got a PL450B in a modded J/L Ti-B host with a G-2 lens, and I just gave it a quick check for divergance, and I found the divergance to be 1.115mrad. The check was done over a distance of 50' (15.25m). :yh:

It may even be a bit better, since I did it alone, and only adjusted the dot size once to what looked to be a minimum size from 50' away.

I've got to imagine that with a 3 element, or acrylic lens, the results would be well within 1mrad. I would swap my lens, but it's integrated into the host, and can't easily be changed.

BTW - The beam is easily seen in dim light, and very well in darkness; it's outputting 327mW with the G-2.

Good luck with your project! :beer:

 

[dden4012]

You can get away with a G2 lens with the single mode. You may not like the box reflection image with the beam dot. I am really partial to the 2 element lens. I use it on just about everything.
The PLTB450B has a nice beam for a mm diode. A flex drive can power it no problem if you give the driver something to shed heat to. The SL hosts with the driver shelf pill work just fine S4 or C6. Pretty much any diode running on 1.8 amps and under can be powered with a single cell and the flex drive.

 

[diachi]

You can get away with a G2 lens with the single mode. You may not like the box reflection image with the beam dot. I am really partial to the 2 element lens. I use it on just about everything.
The PLTB450B has a nice beam for a mm diode. A flex drive can power it no problem if you give the driver something to shed heat to. The SL hosts with the driver shelf pill work just fine S4 or C6. Pretty much any diode running on 1.8 amps and under can be powered with a single cell and the flex drive.

Yeah, flexdrive is a good choice for these LDs. That's what I'm using in my NDB7242E build, works great!