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mattydc

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Morning guys,

Been reading up topics for a few days now with interest. Seems like a good thing you have going on here :yh:

Introduction : Matt, 34, UK born and bred. Have a broad interest in technology but mainly the EM spectrum and computers. Been a licenced radio amateur for years so have played at all sorts of frequencies from long wave to microwave. Lasers were always something that interested me as a kid but could never afford. I guess it was something about that line of sight principle that got me interested. In radio we have similar antenna's to a laser, directional and focussing all power in one direction. All good fun and science.

Upto now i've only really played with the cheap red pointers and had a few green higher power 532nm portable lasers. I believe these are never upto the power they specify though and disappointed that so many sellers seem to quote ridiculous things that are untrue. I hope to learn more from here though and purchase my first high power burning laser from a reliable source.

I'll leave it here for now before I get carried away and name and shame places i've brought unreliable lasers from. If only i'd known about this place before! Cheers and :beer:'s.

Matt
 

CurtisOliver

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Welcome to the forum Matt, from another fellow brit. :)
As for these cheap 532's. If the power stated is say a ridiculous 5000mW, then the laser is far underspec as they lie anywhere in between 80-150mW depending on the model.
Where abouts are you in the UK?
 

BowtieGuy

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Welcome to LPF, Matt! :beer:
Nice intro, we've got some great, active UK members here.
 

mattydc

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Thanks @BowtieGuy and @Alaskan

@CurtisOliver i'm up in the cold hills of Yorkshire and have been for (to many!) years but grew up 'dun souff' lol. I thought I could avoid the ridiculous claims by not buying anything ridiculous but it doesn't seem to work like that... My first green was 50mw eBay/China special back in about 2005 and to my knowledge that was probably near true. Now my kids are getting older and the eldest is showing interest in such things with a sensible approach I figured a upgrade was in order.

Brought a 200mw recently from a UK based company claimed to do balloon popping and plastic melting. Of course it came exact style of the one I got 12 years ago, and don't seem a lot brighter. It actually showed a triangle shape like a slice of cake coming out of the dot at random times. The seller claimed a dirty lens and I should clean it, I refused as it wasn't there all the time and brand new so sent it back. They have now confirmed receipt and agreed to send me a tested replacement that should live up to the specification... We shall see.

In the meantime i've contacted a few sellers about getting a blue burner and a green with a great beam, preferably with similar host and battery size and have no response apart from one. They promptly removed all 532's from the store and said they recently found 200mw+ 532's are unstable so temporarily removed... Suspicious. The 520's are crazy money but green is good. I'm thinking a Thor H2 445nm should make a good burner that takes high capacity batteries but 520nm for green is just way expensive. Ideally i'd like something I can fit a beam expander on so that rules out the small 303 types. More research needed I think.

Matt
 

lasersbee

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:wave: Welcome to the Forum Matt...
Enjoy your stay and be Laser Safe.

Jerry
 

CurtisOliver

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Nice area up in Yorkshire. Haven't been up there myself, but it holds some lovely landscape.
Yep, most cheap greens made by China actually contain the same or very similar 532nm modules in them from what I have found. I have a cheap pen pointer, a 302 and a built-in li-ion that all behave the same power wise.
That faulty 532, as well as referring to them as unstable is actually to do with the transverse mode shifting. These lasers should be TEM00, but sometimes they can shift to TEM01.


Also they don't have to have the power symmetrically distributed, so one dot could of been brighter than the other giving you the illusion of a triangle.
The greater intensity of one dot would make the bloom appear like this.
 
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mattydc

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Hi guys,

I've tried to upload a picture of what I got from the 200mw green which prompted seller to say a dirty lens.
I don't know if this will work or not with me being a new member. I'd say the dot was near TEM00 but just this smudge which would appear and disappear. Either way no burning potential whatsoever and totally not as described. Hopefully a replacement will be a little better. I shall do a full review on the experience if anyone is interested.

https://ibb.co/g2tPAw

https://ibb.co/g2tPAw

Matt
 
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Alaskan

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Could be a dirty lens, but looks more like splash from a cheap laser pointer to me.
 

lasersbee

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Yeah... looks like some dirt on the lens somewhere..
The 2nd and 3rd photos seem to show some lens
artifact streaking.

Jerry
 
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Alaskan

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Jerry probably has that one right, I take that back, probably just dirty. That pattern even looks a bit like a finger print pattern to me.
 

CurtisOliver

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Ok, definitely not mode shifting. Looks like typical splash to me now we’ve got images.
 
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mattydc

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Guys thanks for the ideas and help. I think the 1st picture was just a little blurry from moving my hand and I got more steady with the 2nd and 3rd. Was just trying to demonstrate that the slice came out at a angle almost in line with the power button (about 20 degrees to the left) no matter which way it was held.

The seller said and I would buy dirty lens as the problem were it not for this slice appearing and disappearing at random. Surely the lens would cause it to be brighter or dimmer depending on the state of the batteries and general brightess of the dot? This pointer gets bright then dim at random at the best of times even with fresh batteries. Yet the slice appears and disappears as well at other random times. I tested tapping the pointer to see if anything was loose but nope. It pretty much seemed to me that depending on angle or pressure on the button was what could cause it to change the most. Also tightening and loosening the battery cap. It most likely was just a cheap pointer ramped up in price by a UK seller? Doesn't look anywhere near a 200mw that I saw on Youtube anyway thats for sure.

Matt
 

lasersbee

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If the artifact is "appearing and disappearing at random"
then it could be a moving lens issue. Have you taken the
lens assembly apart yet... :thinking:

Jerry
 
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BowtieGuy

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I've had similar artifacts show up before, and usually, as Jerry mentioned, it was a loose/wobbly lens issue.
I've also had that same issue where the artifact didn't move with lens rotation, and found the problem to be a diode that was not squarely pressed into the module, and thus causing a reflection from the inside of the lens holder.

Edit: Does the beam come out straight from the laser, or does it come out at an angle?
 
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