Question on 405nm beam

gregma · Dec 1, 2015

Just got a few new lasers, I'm still waiting for my LPM materials to get here to get them measured, but when looking at the 75mW 405nm laser focus all the way out, I noticed some spots in the beam. Are these normal? I haven't checked my other lasers, but will.

Pi R Squared · Dec 1, 2015

Yes this is normal, I have several lasers with this, it is a tiny flaw in the emitter or more likely the glass window in the diode can, or tiny particles on the glass, I don't recommend trying to clean the glass window in the diode, sometimes this goes badly, keep the lens on all the time so no dust gets on the diode window.

Alan

BowtieGuy · Dec 1, 2015

Looks like it may be dirt on the lens, do the dots move when you rotate the focus adjuster, if so then the contamination is on the lens.

Lifetime17 · Dec 1, 2015

Hi,
Could be something simple links,a dirty lens or diode window. That happened to me a couple,of times to. A little alcohol on a swab not to much let it dry then use air for computer keyboards. This is to make sure you don't have any lint from the swab on on the diode window . If you do it will burn onto the window you don't want that. Hope it helps a little

Rich

Pi R Squared · Dec 1, 2015

I wouldn't clean the diode window over something that small, I have larger dots in my best laser but you can only see them when it's unfocused so it doesn't matter, and mine don't rotate with the lens, that means the diode, if it's not broke don't fix it, it's too easy to make it worse, however Bowtie is right, see if they rotate when focusing. I keep a lens cap on my lasers because I live in a dusty environment and it's easy to ruin a lens by burning someting on to it so it can't be cleaned, although this generally applies mostly to more powerful lasers.

Alan

BowtieGuy · Dec 1, 2015

That's actually pretty clean looking; I've seen a lot worse than that, heck I own a lot worse than that!

gregma · Dec 1, 2015

Pi R Squared said:
Yes this is normal, I have several lasers with this, it is a tiny flaw in the emitter or more likely the glass window in the diode can, or tiny particles on the glass, I don't recommend trying to clean the glass window in the diode, sometimes this goes badly, keep the lens on all the time so no dust gets on the diode window.

Alan

Aha! Thank you for the info.

gregma · Dec 1, 2015

BowtieGuy said:
Looks like it may be dirt on the lens, do the dots move when you rotate the focus adjuster, if so then the contamination is on the lens.

Haven't checked when rotating the adjuster, will do that tonight.

gregma · Dec 1, 2015

BowtieGuy said:
That's actually pretty clean looking; I've seen a lot worse than that, heck I own a lot worse than that!

Well, I haven't checked any of my new lasers yet, so I might see a lot worse

I only checked this one because the dot looked really weird with this laser. From about 10' it looks like it has a central focused dot, with two tiny dots on the right and left. I tried to take a pic, but wasn't successful. Have to figure out how to take good laser pics.

gregma · Dec 1, 2015

Pi R Squared said:
I wouldn't clean the diode window over something that small, I have larger dots in my best laser but you can only see them when it's unfocused so it doesn't matter, and mine don't rotate with the lens, that means the diode, if it's not broke don't fix it, it's too easy to make it worse, however Bowtie is right, see if they rotate when focusing. I keep a lens cap on my lasers because I live in a dusty environment and it's easy to ruin a lens by burning someting on to it so it can't be cleaned, although this generally applies mostly to more powerful lasers.

Alan

Although I won't bother with the cheaper lasers, I think I'll try to find a lens cap for the three more expensive ones. Yes, $30 to me is expensive

gregma · Dec 1, 2015

Lifetime17 said:
Hi,
Could be something simple links,a dirty lens or diode window. That happened to me a couple,of times to. A little alcohol on a swab not to much let it dry then use air for computer keyboards. This is to make sure you don't have any lint from the swab on on the diode window . If you do it will burn onto the window you don't want that. Hope it helps a little

Rich

Thanks for the info!

diachi · Dec 1, 2015

Jeez man, are you going for the record? 5 posts in a row!

You should use the multiquote button to quote multiple people or edit your latest response.

gregma · Dec 1, 2015

diachi said:
Jeez man, are you going for the record? 5 posts in a row!

You should use the multiquote button to quote multiple people or edit your latest response.

Good idea! Sorry about that

diachi · Dec 1, 2015

gregma said:
Good idea! Sorry about that

It's all good

RB astro · Dec 1, 2015

gregma said:
Well, I haven't checked any of my new lasers yet, so I might see a lot worse I only checked this one because the dot looked really weird with this laser. From about 10' it looks like it has a central focused dot, with two tiny dots on the right and left. I tried to take a pic, but wasn't successful. Have to figure out how to take good laser pics.

That's normal for a 405nm dot, it will look like that.
It's the way the light waves interfere with each other.

:yh:

gregma · Dec 1, 2015

RB astro said:
That's normal for a 405nm dot, it will look like that.
It's the way the light waves interfere with each other.

:yh:

Good to know, thank you! I thought perhaps it was defective, but so far everything I've gotten from him has been outstanding quality.

Question on 405nm beam

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