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PLTB450B raw output divergence

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May 15, 2016
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So, I have a Gatling laser, which most likely uses a PLTB450B diode. Its raw output has over 90° of full angle divergence, hitting the host itself by quite a bit if unscrew the lens holder, and even a bit of the heatsink.
Is this normal? According to some datasheed I found online, the typical fast axis FWHM divergence for that diode is 23°. Apparently that is the divergence where it is at or above half power, with the center being the max. So, Is the over 90° for the full beam normal, or is the diode defective?
Also, why does it have a bit less divergence than the M140, if the slow axis of the raw output is relatively less divergent? That means the thinner axis of the beam when it hits the lens would be even thinner, having a higher minimum possible divergence, doesn't it?
 



gazer101

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That image does seem quite a bit more divergent than my laser when I unscrew the lens, but that could be due to some sort of tiny optics they put in front of the diode emitter itself (not necessarily because its divergence is bad). So long as you don't get a flashlight-like beam when you screw in the lens you should be fine
 
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That image does seem quite a bit more divergent than my laser when I unscrew the lens, but that could be due to some sort of tiny optics they put in front of the diode emitter itself (not necessarily because its divergence is bad). So long as you don't get a flashlight-like beam when you screw in the lens you should be fine
There is nothing in front of the diode window, I had do clean it once because a piece of tape I put on the lens holder's threads fell in there with the laser powered on, and it was perfectly flat.
The beam with the lens is perfectly fine, just slightly off-center and cropped by quite a bit. It gets cropped even if I make the lens touch the heatsink.
Expanded dot ( \ / shape from being off-center):
Dot with the lens touching the heatsink:
Notice the slightly curved edges of the rectangle. The fuzzyness is because I used the old stock lens which got very fuzzy over time, didn't bother to unscrew the G7 and have to adjust the focus all over again.
By the way, the laser has probably lost some power over time, it could ignite white paper when focused when it was brand new, but now it only makes some embers, even with the G7 lens.
 

ArcticDude

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There is nothing in front of the diode window, I had do clean it once because a piece of tape I put on the lens holder's threads fell in there with the laser powered on, and it was perfectly flat.
The beam with the lens is perfectly fine, just slightly off-center and cropped by quite a bit. It gets cropped even if I make the lens touch the heatsink.
Expanded dot ( \ / shape from being off-center):
Dot with the lens touching the heatsink:
Notice the slightly curved edges of the rectangle. The fuzzyness is because I used the old stock lens which got very fuzzy over time, didn't bother to unscrew the G7 and have to adjust the focus all over again.
By the way, the laser has probably lost some power over time, it could ignite white paper when focused when it was brand new, but now it only makes some embers, even with the G7 lens.
So basicly same question on here?
 
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Messages
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So basicly same question on here?
Not really, this question is about the divergence of the PLTB450B diode in particular, that one is about why the divergence increases on more powerful blues, which eventually became about which lens I should use considering the raw output of the gatling.
I said the same things about the output of my gatling because the previous reply talked about the beam cheracteristics with the lens.
 
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