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By Jon Singer on November 16, 2011
[Started on May 15, 2011.]
This page is intended partly as a followon to
the “Easy TEA Laser” page,
and partly as a standalone project. It describes a relatively powerful room-pressure nitrogen laser.
Before we get any further along, we need some safety information and a disclaimer.
!! WARNING !!
If you build this project you do so at your own discretion, and at your own risk.
These lasers use high voltages, and capacitors that can store lethal amounts of energy. They put out invisible ultraviolet light that can damage your eyes and skin. It is extremely important to take adequate safety precautions and use appropriate safety equipment with any laser; and it is crucially important with lasers that involve high voltages and/or produce invisible beams!
In addition, this particular laser uses two open spark gaps, which will damage your hearing if you do not use adequate ear protection. I strongly suggest that you acquire and use at least a pair of sound-protection earmuffs of the type used by shooters at rifle and pistol ranges; they look about like this:
Figure 1: Hearing protection
(These cost me $35, and they are definitely worth it.)» Read the rest
By Jon Singer on August 31, 2011
This project is part of a larger project I have in mind, which requires a mode locked laser. (That project, or at least its earliest stage, is described in TJIIRRS #23.) I initially tried passively mode locking a blue diode laser, but that proved to be somewhat fraught, and I need to find an appropriate detector before I proceed further with it. (I may also need to try active or hybrid locking.) For the moment, I have set that approach aside in favor of a different one. We have an old Coherent CR-599-04 jet dye laser and a Coherent 5920 dye circulator, and I decided that it might be a good idea to attempt to get these running as a possible alternative path.
I thought about using the blue diode laser to pump the CR-599, but there are two apparent obstacles. First, the blue diode is a multimode device, and it may not be possible to focus the beam from it down to a suitable spot size: jet dye lasers generally utilize spot size of less than 50 microns diameter, and I think they prefer 10 or 20 microns. Second, it is difficult to find a low-threshold dye that absorbs » Read the rest
By Jon Singer on May 24, 2011
TJIIRRS: Number 22
Some Adventures with a Commercial Excimer-Laser Head
(21 May, 2011, ff)
Some time ago we were able to acquire, on eBay, an item that is clearly the head of a very small excimer laser. It has room for two preionizers; but when we got it, only one was present, and the other edge of the cathode had a white deposit on it that I was uneasy about.
(The deposit is not visible in these photos.)
For quite a while I didn’t do anything with this structure, but it has been on my mind a lot, and a few days ago I dragged it out and started thinking about it in earnest. I usually avoid commercial parts, but here was this very fine piece of equipment, lacking only a few capacitors, a switch, and some gas; and I do have a project or two in mind that could use it.
Beginning of the Build
I have started to build a box for the head:
I have also made a new preionizer for it:
(I got some 5-mm borosilicate tubing on eBay. The vendor specified it as having 3.4-mm ID, but a 1/8″ rod failed to fit » Read the rest
By Jon Singer on May 23, 2011
TJIIRRS, Report Number 15A:
Toward a Straightforward DIY Flashlamp-Pumped Organic Dye Laser
Step 1, First Proof of Principle: A Minimalist Machine
(Is it possible to threshold a dye laser with only 6 Joules input?)
(December 19, 2009, ff)
This page details the construction of a prototype dye laser that is intended for initial checking of some parameters for example, I want to know whether a simple design will threshold “easy” dyes with minimal input energy. In principle, the answer is already known to be “Yes”; but in practice it may not be so easy. The laser will be operating close to margins, and any sacrifice of efficiency will be difficult to work around.
This preliminary design uses a commercial capacitor and a commercial spark gap switch, both of which I hope to eliminate in later designs. The machine that I’m working toward will almost certainly use a commercial flashlamp, though, because xenon is the most efficient emitter in the wavelength regions of interest for pumping organic dyes.
It will, very likely, also use commercial laser mirrors. Quite a few dye lasers have been operated with simpler mirrors, which could be homebrewed, but I am not at all certain
By Jon Singer on May 21, 2011
Interim Research Reports
The Joss Research Institute
- Recent Ceramic Happenings, early Spring, 2005
- Yohen Tenmoku and a plant note or two, late April, 2005
- Bringing up the Molectron Nitrogen Laser
- Results of a Late Spring Δ10 Gas Reduction Firing
- Thoughts About High-Performance Nitrogen Lasers, with a set of follow-on pages in which I actually try to do something about it.
- Item #6 is on hold at the moment.
- “Platzepuss”: An electric-powered radio-control motorized Platz-Gleiter model (Work in progress, currently on hold while I deal with other issues.)
- The Hughes “M-60” rangefinder laser (Likewise on hold for a bit.)
- An Ultraviolet Laser Dye
- Inexpensive Laser Dyes for Do-It-Yourselfers, with follow-ons about pumping and tuning
- A brief report on one way to construct a dye cuvette for nitrogen- or excimer- laser pumping
- A simple and straightforward 5″ refracting RFT built from surplus lenses, PVC pipe (or leftover wood veneer), and a few other things…
- Some Handy Techniques, including a mirror mount that is entirely built from pieces you can buy at a hardware store and a hobby shop…
- An RGB “White Light” dye laser using a single cuvette of dye solution…
- Toward a Simple and Straightforward Lamp-pumped Organic Dye Laser, Part
By Jon Singer on May 16, 2011
An Examination of the Amateur Scientist Circuitboard Nitrogen Laser
Many Do-It-Yourselfers have built nitrogen lasers, often from a design published in the Amateur Scientist column of Scientific American magazine. This page discusses the text of that column in some detail, and shows several ways in which the explanation of the design and how it operates is faulty.
In the Amateur Scientist column, on page 122 of the June, 1974 issue of Scientific American, there was a design for a tabletop nitrogen laser. It was written by someone named Jim Small, who was a student at MIT at the time. The article was later republished in the Scientific American book Light and Its Uses, and is also on the CD of Amateur Scientist columns, which you can get from The Society for Amateur Scientists. I have also found this CD available from The Surplus Shed, and from American Science and Surplus.
The design isn’t bad at all: it’s easy to build, easy to operate, and puts out enough energy to drive a
By Jon Singer on May 15, 2011
Joss Institute Projects:
A Straightforward TEA Nitrogen Laser for the Do-It-Yourselfer
(A “My First Laser” Project
That Evolves into a Higher-Performance Laser)
[Started on April 8, 2011.]
This photo shows a fairly complex version of the laser in operation. (The initial version is simpler, and easier to construct.) The output is not visible to the eye; the fluorescent objects on the left and right indicate the presence of the beams: partly because there are no mirrors, this laser produces two.
Amateurs have been building lasers since fairly shortly after the laser was invented. Several laser projects even appeared in the late (and much lamented) Amateur Scientist column in Scientific American, which is now, fortunately, available in its entirety on CD-ROM. There are also various pages on the Web that provide information about DIY lasers of various sorts, and I provide links to some of them at the end of this page.
Unfortunately, I see quite a few videos on YouTube in which someone has bought a little laser module and hooked it up to a battery; they then proudly claim that they have built a laser. That’s pretty sad, especially when almost any of them actually » Read the rest
By Jon Singer on May 10, 2011
TJIIRRS: Number 5 of an Ongoing Series;
Nitrogen Laser Considerations for the DIYer,
With a View Toward the Design and Construction
of a High-Performance DIY Laser
Part 1 of a Multipart Report (see Links)
(16 September, 2009: this is a 2006 rewrite and continuing revision of a page I originally wrote in July of 2005.)
I have been rereading some papers on nitrogen and excimer lasers, and rethinking my understanding of the important characteristics of a nitrogen laser. Some of the issues are simple and some are fairly obvious, but some are not so easy to understand. This page attempts to examine and clarify issues pertinent to DIY high-performance nitrogen lasers, and to take a look at what you need to know in order to build one. Follow-on pages examine specific designs and the performance that you can expect to achieve with them.
If you want a high-performance nitrogen laser and you can’t afford to buy one, it is certainly possible to construct one; but even if you start with a good design, there is only a modest chance that you will obtain the specified performance level on your initial attempt. The nitrogen laser is not a high-tech device, but
By Jon Singer on May 10, 2011
Lasers at the Joss Research Institute
- A straightforward low-pressure nitrogen laser design intended for DIY folks
I am also working on some more advanced designs; you may want to take a look at the low-pressure nitrogen laser pageset that is among my research reports, though you will want to be aware that I include lots of information about failures as well as successes, so you are probably in for a bit of a slog.
- An unhappy discussion of the Scientific American “Amateur Scientist” nitrogen laser or, to be more accurate, of Jim Small’s explanation of how it works.
- Rebuilding a damaged Avco-Everett C5000 nitrogen laser head that we acquired surplus on eBay
- Testing and using a surplus Molectron [low-pressure] nitrogen laser, also acquired on eBay (includes some information about tuning organic dyes that you are pumping with the nitrogen laser)
- Repairing, checking, and using a PRA LN-1000 [TEA] nitrogen laser, also acquired on eBay, with a note about tuning organic dyes under TEA-N2 pumping
- A bit more information about nitrogen-pumping organic dye lasers
- A “photographic tuning curve” for 4-Methyl-Umbelliferone, pumped by a low-pressure nitrogen laser
- A photographic tuning curve for 7-Diethylamino-4-Methyl-Coumarin, under flashlamp pumping
- A flashlamp-pumped organic dye laser that