Glow in the Dark Fun

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Hey,

I'm Dave and just recently got into lasers after coming up with an idea. I'm a freshman in college and was thinking it'd be cool if I could make a glow-in-the-dark (GITD) poster that could be "written" on with a laser pointer to put in my dorm room. After looking around the net it looks like I'm not the first person to come up with this idea, and I've seen the GITD BB's with the Blu Ray laser pointer and such. It looks pretty cool.

I tried making a Blu Ray laser pointer with minimal success - it's not lasing, just giving off the purple LED glow. I think I was too rough with it, probably broke it.

Then I realized: originally I thought I would just have to get a small wavelength laser pointer to excite the GITD compound. But then I found some GITD stuff that instead of glowing green, it glows red.

Question: I've heard the general rule of thumb with GITD stuff is a smaller wavelength than is emitted is required to excite the GITD compound. Hence, green GITD stuff is excited by blue, violet, ultraviolet, etc. So it would still hold that if I got red GITD paint (it glows red when it's excited), it should be excited by green, blue, violet, ultraviolet, etc. Is this correct?

If this is true, I'm just going to buy a cheap green laser pointer. Does anyone have any suggestions for a nice 5 mw green laser pointer? I'm looking for cheap in price but not cheap in quality. Should I even bother checking eBay?

Thanks!

Dave

 

[iLikeLight]

Welcome to LPF!

http://www.optotronics.com/green_pens.php has a $47 4.99 mW green pointer (With shipping it comes to $53.98). I have never used it, but Optotronics has a reputation for high quality lasers.

There is a 30 mW green on that same page for $75.

 

[Benm]

Question: I've heard the general rule of thumb with GITD stuff is a smaller wavelength than is emitted is required to excite the GITD compound. Hence, green GITD stuff is excited by blue, violet, ultraviolet, etc. So it would still hold that if I got red GITD paint (it glows red when it's excited), it should be excited by green, blue, violet, ultraviolet, etc. Is this correct?

This concept is generally correct, phosphorescence always occurs at a longer wavelenght that the one used to excite the phosphor. Without going into detail, it's worth to notice that depending on the compond, there has to be a certain difference between the wavelegths for this to work.

That said, it probably will work, but you should check with the company that makes the compound which wavelegth is required.

Also, as red light is not as visible as green, you might be disappointed with the resulting brightness... it's not as impressive as hitting the typical green GTID compound with blue or uv light.