Pin hole for clean up a focused laser ?

[Chimo2]

HI

have search on forum and not find clear answer

for a industrial application i need to use a focused laser
but my problem was
that i got the expected laser spot + image of the internal of the diode

so i need to remove this and keep only the Gaussian laser beam
i try whit pin hole mounted right on the diode but it hard to adjust
specially whit very small pinhole

i power diode well under threshold point and under microscope i
move pin hole until i see the spot but ,i not certain that laser
will exit same spot that in led mode ?
and this was not really eyes safe to ....

any other subjection or optic trick ?

my setup was

Aixiz laser module + glass lens
focus beam to spot of 0.004" (4 mil) @ distance of 2"
image of laser internal = ~0.080 to 0.100"
i clearly see on target the diode die and bonding wire ...

Best regard

 

[Wolfman29]

You get an image of the LD projected? That's not normal....

 

[Chimo2]

Hi

LD internal was filled whit light so lens simply focus and project it on my target ?
if i was not focused i not have that issue

my 2 module have do the same thing

may also take problem back way it you look right away on the module lens
you will see the spot and the internal

then beam was much smaller that the 1.6mm hole of the LD

Best regard

 

[Bluefan]

If you want to clear up a beam profile of a laser diode then after collimation you can focus on the pinhole and collimate the beam after that, which then can be focussed:
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