Forums

strange blue laser optics

Started by John Larkin March 12, 2020

I got a couple of these, to maybe cure UV-set epoxy.

https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

It came with a big lithium battery and a charger.

Two weird things:

If I shoot it at a white wall, I can see the spot with my right eye,
but not with my left one. The right eye has had cataract lens
replacement.

I got a mild headache from just looking at the spot on the wall for
under a minute total. I also get a mild headache from using a UV
flashlight.


-- 

John Larkin         Highland Technology, Inc
picosecond timing   precision measurement 

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

fredag den 13. marts 2020 kl. 00.02.22 UTC+1 skrev John Larkin:
> I got a couple of these, to maybe cure UV-set epoxy. > > https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 > > It came with a big lithium battery and a charger. > > Two weird things: > > If I shoot it at a white wall, I can see the spot with my right eye, > but not with my left one. The right eye has had cataract lens > replacement. > > I got a mild headache from just looking at the spot on the wall for > under a minute total. I also get a mild headache from using a UV > flashlight. >
https://youtu.be/-2crWR1lg6s
On Thu, 12 Mar 2020 16:25:21 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>fredag den 13. marts 2020 kl. 00.02.22 UTC+1 skrev John Larkin: >> I got a couple of these, to maybe cure UV-set epoxy. >> >> https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 >> >> It came with a big lithium battery and a charger. >> >> Two weird things: >> >> If I shoot it at a white wall, I can see the spot with my right eye, >> but not with my left one. The right eye has had cataract lens >> replacement. >> >> I got a mild headache from just looking at the spot on the wall for >> under a minute total. I also get a mild headache from using a UV >> flashlight. >> > >https://youtu.be/-2crWR1lg6s
My eye doctor, a really cool guy, blasted my right eye with his old CW argon ion laser, to spot-weld my retina to the back of my eyeball. That kinda hurt. He's Thai and his first and last names are both about 20 characters long, so everybody calls him Dr B. My retina was mostly detatched and getting worse, so he came in at 10 PM and fixed it. He also removed a secondary cataract by cutting a hole in the rear of my lens capsule with a pulsed yag. The blue "burning" laser makes a very hot spot if you focus it carefully. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On 2020/03/12 4:02 p.m., John Larkin wrote:
> > > I got a couple of these, to maybe cure UV-set epoxy. > > https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 > > It came with a big lithium battery and a charger. > > Two weird things: > > If I shoot it at a white wall, I can see the spot with my right eye, > but not with my left one. The right eye has had cataract lens > replacement. > > I got a mild headache from just looking at the spot on the wall for > under a minute total. I also get a mild headache from using a UV > flashlight. > >
I 'like' the description "High quality and perfect design." where have we heard 'perfect' before? And why should you trust them? I'm very suspicious of any and all unregulated products from China. They claim it is 405nm, but unless you have a spectrum analyzer you have no idea if it is also emitting UV-B or other dangerous UV radiation. Perhaps you could lend one to Winfield - I imagine he has one of those S.A.s rattling around his shop! Wear proper UV safety glasses (at a minimum UV-A/B rated sun glasses) when using this. https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/uv-protection/faq-20058021 I'd treat it like light from an arc-welder, dangerous until proven otherwise. John :-#(#
On Thu, 12 Mar 2020 16:54:46 -0700, John Robertson <spam@flippers.com>
wrote:

>On 2020/03/12 4:02 p.m., John Larkin wrote: >> >> >> I got a couple of these, to maybe cure UV-set epoxy. >> >> https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 >> >> It came with a big lithium battery and a charger. >> >> Two weird things: >> >> If I shoot it at a white wall, I can see the spot with my right eye, >> but not with my left one. The right eye has had cataract lens >> replacement. >> >> I got a mild headache from just looking at the spot on the wall for >> under a minute total. I also get a mild headache from using a UV >> flashlight. >> >> > >I 'like' the description "High quality and perfect design." where have >we heard 'perfect' before? And why should you trust them? > >I'm very suspicious of any and all unregulated products from China. They >claim it is 405nm, but unless you have a spectrum analyzer you have no >idea if it is also emitting UV-B or other dangerous UV radiation. >Perhaps you could lend one to Winfield - I imagine he has one of those >S.A.s rattling around his shop! > >Wear proper UV safety glasses (at a minimum UV-A/B rated sun glasses) >when using this. > >https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/uv-protection/faq-20058021 > >I'd treat it like light from an arc-welder, dangerous until proven >otherwise.
Well, toothpicks are dangerous too, if you poke one in your eye.
> >John :-#(#
It seems to work. The spot, well focussed, feels very hot on my hand, so it's a lot of power. It came with a spot-matrix-pattern diffuser installed, which might be prudent to leave in place for curing epoxy. Amazing for under $10. I wish I had a wideband spectrum analyzer, ideally something like 350 to 1700 nm. All the available OSAs go for extreme resolution over a narrow range, well under an octave. I just want to know about what the wavelength of a laser or LED is. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
John Robertson <spam@flippers.com> wrote in
news:mcudnQEjsuRaVvfDnZ2dnUU7-X3NnZ2d@giganews.com: 

> I 'like' the description "High quality and perfect design." where > have we heard 'perfect' before? And why should you trust them? >
Because they are such 'great businessmen'. Finished at the top of their class... All work is performed by stable geniuses. But all the facts about how they operate are 'classified'.
On 13.03.20 12:59 am, John Larkin wrote:
> All the available OSAs go for extreme resolution over a > narrow range, well under an octave. I just want to know about what the > wavelength of a laser or LED is.
Available as in available at your shop? Otherwise, there are quite a few good (but $$$) options, e.g. https://www.highfinesse.com/en/spectrometer-osa/laser-spectrum-analyzer.html. &mdash; David
On Thursday, March 12, 2020 at 8:59:37 PM UTC-4, John Larkin wrote:
> > I wish I had a wideband spectrum analyzer, ideally something like 350 > to 1700 nm. All the available OSAs go for extreme resolution over a > narrow range, well under an octave. I just want to know about what the > wavelength of a laser or LED is.
If you only want an approximate number you can get that by comparing the color by eye. Look at the laser spot on white paper, look at a known LED on the same white paper. You should be able to get within a few 10s of nm. The eye is very sensitive to pure colors. -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
John Larkin wrote:
> On Thu, 12 Mar 2020 16:54:46 -0700, John Robertson <spam@flippers.com> > wrote: > >> On 2020/03/12 4:02 p.m., John Larkin wrote: >>> >>> >>> I got a couple of these, to maybe cure UV-set epoxy. >>> >>> https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 >>> >>> It came with a big lithium battery and a charger. >>> >>> Two weird things: >>> >>> If I shoot it at a white wall, I can see the spot with my right eye, >>> but not with my left one. The right eye has had cataract lens >>> replacement. >>> >>> I got a mild headache from just looking at the spot on the wall for >>> under a minute total. I also get a mild headache from using a UV >>> flashlight. >>> >>> >> >> I 'like' the description "High quality and perfect design." where have >> we heard 'perfect' before? And why should you trust them? >> >> I'm very suspicious of any and all unregulated products from China. They >> claim it is 405nm, but unless you have a spectrum analyzer you have no >> idea if it is also emitting UV-B or other dangerous UV radiation. >> Perhaps you could lend one to Winfield - I imagine he has one of those >> S.A.s rattling around his shop! >> >> Wear proper UV safety glasses (at a minimum UV-A/B rated sun glasses) >> when using this. >> >> https://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/uv-protection/faq-20058021 >> >> I'd treat it like light from an arc-welder, dangerous until proven >> otherwise. > > Well, toothpicks are dangerous too, if you poke one in your eye. > >> >> John :-#(# > > > It seems to work. The spot, well focussed, feels very hot on my hand, > so it's a lot of power. It came with a spot-matrix-pattern diffuser > installed, which might be prudent to leave in place for curing epoxy. > Amazing for under $10. > > I wish I had a wideband spectrum analyzer, ideally something like 350 > to 1700 nm. All the available OSAs go for extreme resolution over a > narrow range, well under an octave. I just want to know about what the > wavelength of a laser or LED is. >
A CD or DVD disk does not help?
On 2020-03-12 19:02, John Larkin wrote:
> > > I got a couple of these, to maybe cure UV-set epoxy. > > https://www.ebay.com/itm/High-Power-Purple-405nm-Pointer-Burning-Light-Beam-Pen-with-Battery-Charger-USA/383162483108?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 > > It came with a big lithium battery and a charger. > > Two weird things: > > If I shoot it at a white wall, I can see the spot with my right eye, > but not with my left one. The right eye has had cataract lens > replacement.
There was a Car Talk puzzler many years ago that hinged on that--optical signalling to the French resistance using UV filters that made the flashes visible to old men (who had had cataracts removed) but not to young German soldiers.
> > I got a mild headache from just looking at the spot on the wall for > under a minute total. I also get a mild headache from using a UV > flashlight.
UV epoxy is usually designed for Hg I-line (365-nm) peak sensitivity. I generally use a 380-nm LED, which works fine. How well does your 405 work? CHeers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com