Danger! New Wish Lasers - No IR Filter

Lew Fong

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Feb 18, 2007
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Hello All,

I was horrified to read the thread confirming that New Wish lasers are "pot-moddable". Please be aware that these lasers do not have an infra-red filter, and are extremely dangerous when modified.

At 5 mw, having no IR filter is not especially hazardous. But when one turns up the power, you've got trouble. There is a failure scenario you must be aware of that is very dangerous.

Once you modify your cheapie to maximum, you are now in danger of cracking the MCA with the additional heat...it is not just the diode that needs heat protection. If the MCA fails, the visible light output will be nil, while the IR output could still be 200 mW or more! I wonder if anyone has been blinded by modifying a New Wish, cracking the MCA, and then looking down into the laser to see what's wrong!

Dr. Fong says," Do not look into the laser with your remaining good eye."

Cheers All,
Lew Fong
 

Catapult

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It's best not to look into the laser diode on or off. It should be treated the same way as loaded firearms. Damage to the eye may not be immediately noticed until later on.
 

2xTrinity

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The way I deal with all laser pointers -- even cheap low power reds -- is that the only time I would ever point one at my face is if it's actually taken apart so I can visibly see that there are no batteries. Checking to see why a laser is not working, even with an IR filter, is very stupid -- there could be a loose conection that you happen to "bump" back into place, or it may be an open circuit that only occurs due to thermal exapsnion -- ie the circuit is "open" when the casing is hot, but when it cools down bam hits you with the direct beam if you look right down the barrel.
 

SenKat

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New Wish Lasers - HAVE IR FILTERS

Lew Fong - please do not quote rumor on here ! New Wish lasers ARE IR filtered. I do not know where you get your information from, but I have personally torn apart MANY of these lasers - and all of them were IR filtered. Someone who purchased one YEARS prior to me purchasing mine tore his apart, and had the exact same result. Prove to me - and the forum - that they are not IR filtered - and I will prove you incorrect. I have had physical proof that they are indeed filtered, so depite the "rumors" about so-and-so burned their eyes out with a New-wish laser...BAH ! Complete fairy tales.
 

pseudonomen137

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I thought they were unfiltered too, but thanks to SenKat I tried it out and made this post here: http://www.lasercommunity.com/viewtopic.php?t=10149

Apparently some people still say they test there's and they don't have an IR filter though, so there may be some imitation product without IR filters.

BTW: I'm currently in the process of doing something to find out for sure whether or not true NewWish 100mW lasers are filtered or not (as well as some other testing), and hope to be able to post the results within 2-3 weeks.


Good point though Dr. Fong. Just replace "NewWish" with "Spymode".
 

luvlasers

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There is a thread on this forum for listing reputable sellers. How about a thread for listing Disreputable (sic dangerous) sellers? Only if it were to be made, don't turn it into a seller bashing thread, just keep to the facts.
 

SenKat

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SWEEEET !!! New Wish Lasers - HAVE IR FILTERS !

luvlasers - that would be an excellent idea - except for the fact that folks fall prey to rumor too often - and hte list would not be "exact"...it would turn into a bashing thread pretty soon, I am sure of it. The mods on here do a REALLY great job at checking hte posts, to make sure folks do not get out of line - but there would be a TON of editing involved on their part, I am sure :(
 

Lew Fong

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Greetings All!
grinser2.gif



I agree with Catapult and 2xTrinity about their prudent approach,which I try to practice when dealing with anything that can go 'boom'...lasers, firearms, rattlesnakes, land mines, etc.

Senkat - nice to meet you. I should have qualified my statements in view of the erudite audience found here. And Luvlasers makes a good point about being factual..we must be scientific!

Senkat - I have only stripped two New Wish lasers. Both were purchased in November of last year from a US dealer. They are commonly found on eBay now. I should make clear that this is but one of several models that New Wish manufactures, as a quick visit to their web-site will attest:
http://www.newwishlaser.com/english/index.htm

However, both of my NW pointers lack the IR filter. This is evidently a new cost-cutting move by NW which is aimed at their least-expensive, lowest power devices. But this is precisely the market that includes many home experimenters who are trying to turn their $25 laser pointers into light-sabres. I have no factual data concerning the official US attitude towards these devices, but it is my sense that the US lets them slip through because they are <5 mW lasers. Having no IR filter in such a device is not especially dangerous. Only when the experimenter tunes them up do they become problematic.

I want to apologize for not being clear...some NW lasers DO have IR filters, of course. But I think it is a good idea to make certain in any given case.

Of course, I could always be wrong about my direct observations. My conclusion about the two pointers I own arises directly from inspection...I did not see a filter in either one. But the accuracy of this observation is predicated upon the knowledge of what an IR filter looks like, and where it should be mounted, and whether or not a complete inspection was made to discover possible hidden features.

I will say that these two pointers are the most handsome of all I own, IMHO. They are bright and stable. So far, I am the only one I know who has been able to dismantle the type, tune it up, and re-assemble it into a good looking pointer again with no visible damage to the exterior case....no mean feat let me assure you! They both peaked out at about 45 mW of green. I have no method available to read the IR output spectrum. Both will just barely go through a black trash bag at close range. I interpret this as a sign of high IR content in the output. They are too dangerous to use for anything, so I rarely touch them anymore.

Senkat - I would be curious to learn of your work on a late-model eBay special NW, to see if you find IR filters in them....Maybe I don't know what I'm supposed to be looking for!

And finally, as nice as it would be to have a Rip Room, where we could tear up bad actors and non-hackers, it is such an anti-PC thing to do anymore. One has to be very careful these days about criticizing anything or anyone.

But at least it's nice to have had your good company here, and your attention for so long at that.

Cheers All,

Lew Fong
grinser2.gif
 

SenKat

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Lew FOng - Thanks for your post ! I have completely dissasembled the all black and all silver models (the black model has a silver tip) in the 50mw category. I saw the IR filter there right on the backside of the ktp crystal, not at the collimating optics. I know some folks are lucky enough to be able to peer into their lasers (with the batteries OUT, of course !) and see the IR filter glued in place on the output optics, but this was not the case with the newwish pointers I had.


So I guess, as usual, the safest way is to ASSUME they have no IR filtering, and work from there...safety first !
 

Lew Fong

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Feb 18, 2007
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Hi Senkat,

Uh....I'm confused. If the filter is on the back side of the KTP, would that not prevent the freq-doubler from working correctly? The filter would have to be transparent at 1064 nm, wouldn't it? Otherwise, how would the pump energy reach the KTP? I thought that the IR filter would be, must be, on the output side of the MCA? What do you mean by the "back" side?

I can believe that filtering @ 808nm after exiting the Nd:YvO4, and thence again at 1064 nm after exiting the KTP would work, but then you need two narrow-band IR filters to accomplish the same thing as a single broad-band filter would at the output of the MCA...that could hardly be very efficient from a cost standpoint at the least. But before I bark too far up this tree I guess I should listen up for more details!

Cheers,
Lew Fong
 

SenKat

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NICE ! I meant the output end of the KTP (the backside as I called it) not the front, where it is bathed in 808nm !! sorry for the confusion !



Lew Fong said:
Hi Senkat,

Uh....I'm confused. If the filter is on the back side of the KTP, would that not prevent the freq-doubler from working correctly? The filter would have to be transparent at 1064 nm, wouldn't it? Otherwise, how would the pump energy reach the KTP? I thought that the IR filter would be, must be, on the output side of the MCA? What do you mean by the "back" side?

I can believe that filtering @ 808nm after exiting the Nd:YvO4, and thence again at 1064 nm after exiting the KTP would work, but then you need two narrow-band IR filters to accomplish the same thing as a single broad-band filter would at the output of the MCA...that could hardly be very efficient from a cost standpoint at the least. But before I bark too far up this tree I guess I should listen up for more details!

Cheers,
Lew Fong
 

pseudonomen137

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Aug 13, 2006
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Yeah, my 50mW also had some sort of IR filter at a 45 degree angle in the beam, deflecting towards something I'm guessing is a photodiode? I didn't really take in depth measurements to see how well it was filtered before destroying it, but it definitely wasn't anywhere near unfiltered.
 

Lew Fong

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Feb 18, 2007
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53
Hey Folks,

OK....so let me be sure I understand: The IR filter you have seen on the NW lasers is mounted on the output end of the crystal assembly, and is sandwiched betweeen the KTP and the collimating lens? What color is it? How thick? Thank You, Senkat!

Hi Pseudonomen,

That angled glass is a beam-splitter...designed to send just a small portion of the total output energy to a photo-diode. This sample is used as negative-feedback for the current servo circuit.

It should be a very thin piece of glass with reflective coefficient no higher than necessary to make the servo operate. Since almost all the energy incident is transmitted, there is no thermal consideration to speak of and the glass can be very thin. The beam-splitter would have little if any IR filtering properties.

The IR filter, on the other hand, would need to be a more substantial piece of glass since it works by absorption and therefore is expected to dissipate a great deal of heat. It should be aqua-blue in color.

Cheers Fellows,

Lew Fong
 

Hemlock Mike

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Dec 16, 2006
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Location
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I'm beginning to believe that Newwish like Leadlight is being cloned in various stages of quality. I have what looks like a newish which I have "modded" to 10 mW. My meters show 0.50 mW of IR output -- Some filters may be better than others.

When the good Dr_Lava meters arrive -- We will all know the truth - A Big Amen :popcorn:

Mike
 

Lew Fong

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Feb 18, 2007
Messages
53
Hi Mike,

Pleasure to meet you, OM!

I am starting to wonder if you are correct about my NW's being clones of some sort....they have a distinctive case design which is my entire basis for their identification. I wish now ( this is a new wish) that I had recorded the identifying nomenclature scribed upon the optics barrel(s), but I did not. I must say that, considering how well built they appear to be ( despite no IR filter) that it is a good job of cloning if true. Nevertheless, clone or not, my original intention here was to warn others about these eBaysers. Perhaps the real question is whether or not these Ebay LP's are actually New Wish designs at all! It would be wrong to condemn the company if their designs are being copied in a less-than-faithful fashion. Perhaps the best warning would be just to carefully inspect any eBay LP that looks like a New Wish?

Cheers and Best Regards,
Lew Fong
 
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