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Joss Research Institute Web Report #10: Laser Dyes for the DIYer

TJIIRRS: Number 10 of an Ongoing Series;

Inexpensive and Readily Available Laser Dyes for the Do-It-Yourselfer

Commercial laser dyes can cost over $100 per gram, and are out of the reach of most DIY laser builders. Furthermore, most chemical companies refuse to sell to individuals these days. This page explores dyes for DIYers, with an eye toward affordability, availability, and performance. Most of these have been tested with nitrogen laser pumping, and a few have been tested with flashlamp pumping.

Although Fluorescein is often available on eBay, it is not necessarily very pure; moreover, Fluorescein is difficult to excite with a nitrogen laser because it has relatively little absorption at 337 nm. (That however, makes it an interesting candidate for longitudinal pumping.) Rhodamine 6G is occasionally available on eBay, as well. Neither of them is usually of laser-grade purity, but that certainly doesn’t prevent them from lasing.

On rare occasions, a few scintillators are available on eBay. I have managed to acquire and lase both PPO and POPOP. Those, however, are the exceptions to the rule, and they cover only part of the spectrum, so it is important to find materials that DIYers can routinely acquire and use.

General Considerations

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Joss Research Institute Web Report #5C [New Series], Part 1

TJIIRRS: Number 5C [New] of an Ongoing Series;

“Theorie und Praxis IIA”:
Revamping the “DKDIY” Laser

Part 1

(15 August, 2006, ff)

This page details the construction of a nitrogen laser that is a follow-on to the “DKDIY”design I published here a few months ago, along with a “How-To” page. Because this material is being written substantially as a historical track of the project as it is taking place, it is not necessarily organized logically. When the design is fully stabilized I will try to provide a “How-To” page for those who want to build a laser of this type.

(Note, 2006 September 27: Between the “DKDIY” laser and this “DK-Plus” laser, I experimented with a larger design, which operated, but not at the performance level I had expected. This appears to have been caused by several factors, some of which I may explore [and, I hope, correct] by returning to that laser and rebuilding it, now that I have this one working well.)

(Note, 05 October, 2009: I am reworking this laser, and I hope to get somewhat better performance from it than I originally did. There are a number of issues involved in the rework, which I

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Joss Institute Projects: Restoring a Commercial Room-Pressure Nitrogen Laser

The PRA LN-1000 Nitrogen Laser

(24 May, 2004 ff, with some additions in 2010 and 2011…)

Overview

The PRA LN-1000 nitrogen laser operates at room pressure, and puts out pulses that are approximately 800 psec long. (At least, that was what the mfr stated. Most room-pressure nitrogen lasers seem to have pulsewidth between about 600 psec and 1 nsec, and I do not yet have an easy way to check, so we’ll leave it as given for now.) The laser is rated to deliver about 1.5 mJ, which corresponds to more than 2 MW peak power. Here are two views of it:

     

We won this laser on eBay, some time ago. When it arrived I found the key broken off in the lock (fortunately all the way in, so I could turn the switch with a screwdriver); some of the screws were missing from the case, and it was clear that not all was well within.

I dusted out the HV section and tried running the laser. It mostly self-triggered, emitting various snorts and barks, and it only occasionally lased; but it was clearly a real machine and not just a pile of scrap. I disassembled the primary spark

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Joss Research Institute Web Report #10c: Naturally Occurring Laser Dyes

TJIIRRS: Number 10c of an Ongoing Series;

Naturally Occurring Compounds Suitable for Use as Laser Dyes

Although most organic materials fluoresce at least a little, there are very few naturally-occurring compounds with quantum efficiency above 0.5 or so. This page discusses some of them, and a few with lower efficiency that have nonetheless been lased.


1: Aesculin

(04 September, 2006)

Aesculin (the modern spelling is Esculin) has been known for many years. It is a hydroxycoumarin compound, related to the umbelliferones. Aesculin can be extracted from the bark and probably the seed husks of Horse-Chestnuts (of which the most commonly grown kind seems to be Aesculus hippocastanum), and presumably also from closely-related species like the various kinds of Buckeye.

Aesculin is brightly fluorescent, particularly in basic solutions. It has been lased and reported in the literature, though only once that I’m aware of. It is a hemolytic toxin, so you shouldn’t eat any horse-chestnuts that you haven’t first crushed and soaked in several changes of boiling water.

I obtained a small quantity of Aesculin Sesquihydrate, and was able to lase it in 95% Ethanol with a small amount of ammonia. Here is a photo:

(The dye cuvette is on

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