My friend has made a working laser that has the following intellectual properties:
1) the more learned the individual is regarding laser construction and operation, the more confused and hostile they are regarding this new laser.
2) The less the individual knows about lasers, the more acceptable the laser is.
This laser has absolutely *NO* optics, NO mirrors, no lenses; none, nada, period. In fact, there are NO optical parts. It is a pure electronic gadget. Light comes out only one end, along the axis.
It was an open-air laser very similar to this one:
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...which might qualify for the OPs laser:
"No mirror was used but a single mirror at the rear of the laser will certainly improve the output."
...except it does put out light at both ends, although:
"The gap between the parallel electrodes was set to 1.2mm on the front, 1.1mm on the rear...Asymmetric output was found between emission from the rear of the laser and the front. The front output was estimated visually to be about 4 times more powerful."
That's a good description of the original work behind the first masers and lasers. Charles Townes's biography ("How the Laser Happened") is great. I think it was somebody on here who recommended it earlier, in fact. Everybody from I.I. Rabi to the cleaning lady told him he was wasting his time.
ISTR a trick using optically pumped low pressure N2 that makes a somewhat dangerous pulsed UV laser described in SciAm AmSci June 1974. The Laser just requires some way of getting enough inverted population and stimulated emmission with gain. Inserted snip here:
An Unusual Kind of Gas Laser That Puts Out Pulses in the Ultraviolet
--------------------- by C. L. Stong June, 1974
---------------------
A RECENTLY DEVELOPED LASER that operates on a six-volt dry battery emits 10 pulses of ultraviolet radiation per minute, each pulse about the size and shape of a broomstick. The pulses range in power from 50 to
100 kilowatts. They strike obstructions end on at the speed of light, with consequences that vary with the nature of the target materials. For example, the pulses bounce off clouds just as radar signals do.
Figure 1: James G. Small's nitrogen laser
With the echoes amateurs can measure distances to reflecting targets miles away; the accuracy is a matter of a few feet. With targets that absorb radiation the effects of impacts range from the emission of fluorescent light to the initiation of chemical reactions, including photochemical reactions. Indeed, as a source of radiation for making photographs the laser is about 10,000 times faster than the high-speed strobe lamps ordinarily used by amateurs.
Many parts of the laser can be assembled with materials that accumulate in the scrap box of anyone whose hobby is electronics. A version of the apparatus that is particularly easy for amateurs to build has been developed and patented by James G. Small, a graduate student of physics at the Massachusetts Institute of Technology. Small explains the principles on which the apparatus is based and the details of its construction and operation
Patents exist (its in the dangerous category for geeks only)
OH masers in star formation regions don't have any optics either.
AFAIK people are still looking for astrophysical visual band optical lasers occurring naturally but so far without success.
ISTR a trick using optically pumped low pressure N2 that makes a somewhat dangerous pulsed UV laser described in SciAm AmSci June 1974. The Laser just requires some way of getting enough inverted population and stimulated emmission with gain. Inserted snip here:
An Unusual Kind of Gas Laser That Puts Out Pulses in the Ultraviolet
--------------------- by C. L. Stong June, 1974
---------------------
A RECENTLY DEVELOPED LASER that operates on a six-volt dry battery emits 10 pulses of ultraviolet radiation per minute, each pulse about the size and shape of a broomstick. The pulses range in power from 50 to
100 kilowatts. They strike obstructions end on at the speed of light, with consequences that vary with the nature of the target materials. For example, the pulses bounce off clouds just as radar signals do.
Figure 1: James G. Small's nitrogen laser
With the echoes amateurs can measure distances to reflecting targets miles away; the accuracy is a matter of a few feet. With targets that absorb radiation the effects of impacts range from the emission of fluorescent light to the initiation of chemical reactions, including photochemical reactions. Indeed, as a source of radiation for making photographs the laser is about 10,000 times faster than the high-speed strobe lamps ordinarily used by amateurs.
Many parts of the laser can be assembled with materials that accumulate in the scrap box of anyone whose hobby is electronics. A version of the apparatus that is particularly easy for amateurs to build has been developed and patented by James G. Small, a graduate student of physics at the Massachusetts Institute of Technology. Small explains the principles on which the apparatus is based and the details of its construction and operation
Patents exist (its in the dangerous category for geeks only)
OH masers in star formation regions don't have any optics either.
AFAIK people are still looking for astrophysical visual band optical lasers occurring naturally but so far without success.
Regards, Martin Brown ===========================================================
The original nitrogen lasers operated at reduced pressure, near 40 torr, and it was thought that higher pressure operation wasn't feasible because of the excited state lifetime and the required rise time of the electrical discharge. Small's patent was basically to roll the large planar capacitors around the discharge tube to make it much more compact. Eventually people figured out how to make them work all the way up to atmospheric pressure, and to even use air as the medium instead of pure nitrogen (at a substantial loss of power). A nitrogen laser is "superradiant" which just means that the optical gain is so high that multiple cavity passes are not required for oscillation, so you can get output with no optics. Putting a reflector at one end of the discharge to reflect that light back to the other end will almost double the power output, however, at the cost of also doubling the pulse length (say from 1 to 2 nsec). A nice resource for this is at
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All that said, from Baer's description I don't think it's a nitrogen or hydrogen (also superradiant) laser, so what is it?
It's a great book. All the experts, even Einstein, thought the required energy inversion state was forbidden by thermodynamics. So Townes just applied force.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
OK book on order. Did Rabi really think it wouldn't work? Rabi oscillations are due to population inversions.
There is often some unknown parameter that makes prediction hard. I hear that the first guys to look for nmr did it in water and couldn't find a signal... problem was the T1 time in water can be seconds or more, they thought it would be much faster. (at least that's the story I hear.. don't know if it's true.)
All sorts of stuff just never got imagined. A few years after they were imagined, kids were doing them as high-school science projects. Lasers, NMR, AFMs, pulsars, all sorts of cool stuff.
I wonder if many more things like that are undiscovered.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
That is the purpose of experimentalists. To take theoretical predictions and test them to destruction. You can never prove a scientific theory but just as in mathematics you can refute one by finding a single counter example that shows the theory is false.
Doing anything the first time is difficult.
I have yet to see a high school project detect pulsars - you need a
*very* large antenna for that! I was amazed by the first AFM I got to play with. It was working less than 300m from a major road in Tokyo.
Graphene and buckyballs as "new" allotropes of carbon are the ultimate examples of things just waiting to be discovered. All you need for the first is Sellotape and graphite and for the latter soot and benzene.
Astronomers had been seeing buckyball spectra for ages before the material was recognised on Earth. Much like Helium in that respect.
Undoubtedly - that is what makes science fun!
Sooner or later someone may actually discover or synthesize a room temperature superconductor. It isn't ruled out by the physics but it is a bit unlikely given how hard people have tried since the LN2 ones.
I agree, very close. I am not cognizant of all of the details, but my understanding is that this "new laser" is by definition at STP since the electronics are surrounded by free air and the nitrogen of that air lases; oh BTW, it cannot be too "ultra" violet because one can see it. No mention of pulsing was made, and this person has no fancy HF equipment, no machining equipment. He likes to make things from commonly found "stuff" (his term).
Sorry; 337nM. Not visible. Use credit card to space (setup) rails. Spacing is semi-critical. Flyback XFMR used, powered from isolated dc side. 6T for primary. Refer to:
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