Sadly that old HeNe is long lost. It went dead when the PSU transformer melted, never got fixed, and it slowly drifted to the bottom of the junk pile and out the door...
The amount they can charge for HeNe these days is outrageous. In '88 I purchased two or three surplus 10mW tubes, takeouts from a failed FedEx business venture where they were going to offer high speed fax. I recall the tubes were about $80 each. A Melles Griot PS, with Alden connectors, was maybe $50, from the same source as here:
The tube in the picture looks very much like the FedEx surplus ones, though perhaps it's a common enclosure.
At one time you could get old Magnavox and Pioneer HeNe-based Laserdisc players for under $50. In addition to the tube all sort of nifty optics, including a small X/Y galvo. Used crop up here and there at garage sales. Haven't seen one in years. Craigslist might be an option other than eBay. They say some of the very early players used polarized tubes, which are/were far less common, and cost a lot more (for a little piece of glass, no less). I had one once, but it gassed out long ago.
Anyway, the following is THE GOTO PLACE for anything laser-related. Sam has published and updated his FAQ for several decades.
Well Gordon you can only get surplus pricing when there is surplus. HeNe lasers are now relatively rare because most of their functions have been taken over by 21 cent diodes, so when someone needs a tube they need it badly enough to pay.
Back in the 80's I got some really nice lenses that I used to make homemade 35mm camera lenses, including several 200mm F/4 Bausch & Lomb copy lenses with internal irises for $8.50 each and a 300mm F/4.5 Carl Zeiss for $25. But the machines those lenses were being retired from are now long gone and the surplus lens market is way more boring than it was in 1990.
I built 0.5mW and 1.5mW lasers from surplus back in the day, I should probably fire them up to see if they still work.
Well yes, that's true of course. More down to supply and demand than surplus I suppose, as he is listing these as new --so the price really isn't all that bad. Dennis wouldn't be selling it for that price unless he could get it, and there are metrological experiments that the cheap ordinary diode lasers can't do. But then, I wonder how many schools do these kinds of experiments these days?
I'm not sure I can get excited about the hording of this junk. I don't have a use for a couple of these, let alone dozens or hundreds! You guys must have huge, empty garages.
Though they might send you a pair that is worthless for 650nm:
"Lens color: Blue or Red Random delivery,mostly is Blue"
I bet these aren't wavelength-cut glasses at all, but "cool sunglasses" of a particular color. They found some optical density data on the Internet for real laser glasses, and just copied it. I mean, at that price I seriously doubt the "red" glasses have any special coating for 600-700nm, and these work only as simple absorption filters for the opposing color.
IOW, wear them to look neato, not to protect your eyes.
Keep at it! Sometimes they just get cranky, and don't want to turn back on after a long sleep.
Warm the glass up in your hands for a while, then try it again.
The other day I was rummaging through some junk in the garage and down came my prototype for a laser pistol, built with a 7" tube and miniature "James Bond" PS. It's in a PVC pipe enclosure, and the glass didn't break, but I'm afraid to try it out. I don't think I've fired it up in maybe 10 years.
Despite the fact that I had no definable use for a 21-cent laser diode, I ordered a bunch anyway. (I mean what else would one expect from a faithful Fourmista lemming?)
So yesterday I get an email encouraging me to "stock up on more" laser diodes. Ever since then, I've been pondering what a person could possibly do with a few hundred schlocky laser diodes.
If there were some appropriately cheap way to modulate the beam, they might provide secure point-to-point communication (I mean some much faster way than just OOK of the diode itself).
Perhaps a spinning mirror could be illuminated by a stack of a few hundred laser diodes. This could then be used to display text or designs on a wall.
Anyway, it makes me wonder if this eBay vendor is nuts, or are there great uses for large quantities of laser diodes that I'm just not seeing? I'd love to come up with some killer use.
You bought a bunch of laser diodes. You obviously like laser diodes. You are probably craving for more laser diodes. What better person to send a mail to reminding them they can get more laser diodes!
I question the sanity of anyone who buys 10 lasers in the first place:)
I do like the spinning idea. I was thinking about this but small scale. One could imagine 8 or 16 or whatever number of these lasers rotated themselves or reflected from a rotating mirror. Would make a dead simple text display projector. Without the complication of a second rotating mirror and having to get in sync'ed up. With the bonus of all that extra brightness.
Now, a Propeller has 32 I/O pins. Two used for serial comms and two for the EEPROM and one for a sync input leaves enough to drive 27 lasers very easily.
There might be a huge laser diode shortage in the near future when we can retire on the profits from reselling our cheap bulk lasers. Every hoarder's dream.
You do need to be careful about any activities that may appear like price gouging in a time of shortage....most states have laws against that. We need to study the business models of the oil companies to see how that works most effectively and apparently legally.
If there were some appropriately cheap way to modulate the beam, they might provide secure point-to-point communication (I mean some much faster way than just OOK of the diode itself).
Peter demonstrated just such a thing late at night at one of the Expos at Parallax (remember when they did that?), he used a solar cell as the collector and was able to transmit audio quite well. I would not have guessed that a solar cell could respond so quickly.
Something else you could do, create an array to make a projectable dot matrix display.
I tested a bag of ten and they're all uniformly pulling 28.3 to 28.8 mA on 5.0 V direct. And they can all be focused to a pretty small dot. The outer housing is a simple friction fit (not threaded). To focus, twist the outer housing in either direction as you push or pull the halves together just a smidge.
I'll build up an S6986 laser sensor with one and report back in few days. Something even bigger is afoot... I can say no more.
Peter demonstrated just such a thing late at night at one of the Expos at Parallax (remember when they did that?), he used a solar cell as the collector and was able to transmit audio quite well. I would not have guessed that a solar cell could respond so quickly.
I won the county science fair in 11th grade with my "Light Beam Communication" project. I build several things (don't EVEN ask how I sent a dollar bill over a light beam); among them was a "Photophone" first invented by Alexander Graham Bell. You talked over a sunbeam! The "microphone" was just a tube with a very thin glass mirror at the end, shiny side out, mounted on a tripod for stability. The thin mirror flexed concave & convex when you spoke into the tube, and thus the reflected sunlight beam was amplitude modulated. The receiver was a concave mirror focused onto a solar cell, which output directly into an audio amplifier. Simple but effective.
No fusion has been achieved, yet, but otherwise the diodes that arrived today have been most impressive.
They cost so little and work so well that they beg to be part of something epic. I like the ideas mentioned. Some form of projection clock is clearly forthcoming. On New Years it could even project onto a public structure for the final countdown.
"...this general rule appears not to apply for all laser diodes including those in many common diode laser modules and even cheap ($9.95) laser pointers. These are now being used routinely for experiments in interferometry and even holography...coherence lengths of 20 cm or more are not unusual. This is similar to that of a typical helium-neon laser..."
I guess Gordon is right that these elcheapo lasers may not cut it but looks like holography with laser diodes is not out of the question.
I am impressed with the distance on these for the price. I have not done any testing but powering with 5V they seem quite powerful, again, for the price!!! Does anyone have any Prop code to use with them yet?
I am impressed with the distance on these for the price. I have not done any testing but powering with 5V they seem quite powerful, again, for the price!!! Does anyone have any Prop code to use with them yet?
I'd imagine the 20 cm bandied about is a "textbook" value of what might be possible, but that assumes a very controlled output. You'd have to out-engineer the slop that these are going to exhibit.
written by a couple of guys that experimented with diode lasers to make holograms, and what they needed to do in order to stabilize the output, including a water-cooled heat sink and a fairly pricey constant current driver. It's not easy to make a hologram with a laser that's changing its frequency maybe dozens of times a second. Can't imagine these diodes not drifting all over the road.
An interesting experiment that would demonstrate how stable the output is would be to make a simple beam splitter interferometer, and point both beams into a phototransistor. Connect it to an amp, and listen to the frequencies beat against one another. A HeNe on a stable solid platform will exhibit relatively little variance. That's what you need for a good hologram. You'll hear the output change if you waft air in front of the detector. The wilder the sound, the more blurry the hologram is likely to be.
Mine arrived today and the package tore and three dropped out. I tested the remaining seven, they work well, and produce a fairly small spot across the room.
Mine arrived today and the package tore and three dropped out. I tested the remaining seven, they work well, and produce a fairly small spot across the room.
I'd imagine the 20 cm bandied about is a "textbook" value of what might be possible, but that assumes a very controlled output. You'd have to out-engineer the slop that these are going to exhibit.
written by a couple of guys that experimented with diode lasers to make holograms, and what they needed to do in order to stabilize the output, including a water-cooled heat sink and a fairly pricey constant current driver. It's not easy to make a hologram with a laser that's changing its frequency maybe dozens of times a second. Can't imagine these diodes not drifting all over the road.
An interesting experiment that would demonstrate how stable the output is would be to make a simple beam splitter interferometer, and point both beams into a phototransistor. Connect it to an amp, and listen to the frequencies beat against one another. A HeNe on a stable solid platform will exhibit relatively little variance. That's what you need for a good hologram. You'll hear the output change if you waft air in front of the detector. The wilder the sound, the more blurry the hologram is likely to be.
Well I've made a controller for work that can has less than 3uAp-p noise on drive current and 0.3mKp-p temperature noise with a butterfly package DFB laser diode. The critical circuits are about $100 in parts all controlled by a Propeller. (could likely get that down to $50 with a re-design if I had to) From various tests, I'm pretty sure that laser has a bandwidth of ~1MHz using this controller. The hard bit with diode lasers is the temperature stability needed. 1mK or less is just TINY. When playing with the thermistor circuits, I could tell if the room lights had switched on/off just by looking at the temperature readings... The worst bits though are temperature gradients compounded by the mismatched coupling between ambient temperature, the feedback thermistor and the laser diode. (oh, and the solder used in thermoelectric coolers creeps as well)
If I was looking for narrow line width at low cost, I'd build an external cavity diode laser with a cheap single mode diode. (I.e.like the link from my first post.) Even without any stabilization, an external cavity diode laser should drift into periods of <1KHz line width. Probably pretty easy to see when the laser is "happy" with a photo-diode and oscilloscope. Anybody going to try that with the 21 cent laser and a dime-store diffraction grating?
Comments
Sadly that old HeNe is long lost. It went dead when the PSU transformer melted, never got fixed, and it slowly drifted to the bottom of the junk pile and out the door...
http://mi-lasers.com/hene-lasers/hene-systems/10mw-633nm-red-hene-laser-system
$900!!
The tube in the picture looks very much like the FedEx surplus ones, though perhaps it's a common enclosure.
At one time you could get old Magnavox and Pioneer HeNe-based Laserdisc players for under $50. In addition to the tube all sort of nifty optics, including a small X/Y galvo. Used crop up here and there at garage sales. Haven't seen one in years. Craigslist might be an option other than eBay. They say some of the very early players used polarized tubes, which are/were far less common, and cost a lot more (for a little piece of glass, no less). I had one once, but it gassed out long ago.
Anyway, the following is THE GOTO PLACE for anything laser-related. Sam has published and updated his FAQ for several decades.
http://www.repairfaq.org/sam/laserfaq.htm
Back in the 80's I got some really nice lenses that I used to make homemade 35mm camera lenses, including several 200mm F/4 Bausch & Lomb copy lenses with internal irises for $8.50 each and a 300mm F/4.5 Carl Zeiss for $25. But the machines those lenses were being retired from are now long gone and the surplus lens market is way more boring than it was in 1990.
I built 0.5mW and 1.5mW lasers from surplus back in the day, I should probably fire them up to see if they still work.
I'm not sure I can get excited about the hording of this junk. I don't have a use for a couple of these, let alone dozens or hundreds! You guys must have huge, empty garages.
Though they might send you a pair that is worthless for 650nm:
"Lens color: Blue or Red Random delivery,mostly is Blue"
I bet these aren't wavelength-cut glasses at all, but "cool sunglasses" of a particular color. They found some optical density data on the Internet for real laser glasses, and just copied it. I mean, at that price I seriously doubt the "red" glasses have any special coating for 600-700nm, and these work only as simple absorption filters for the opposing color.
IOW, wear them to look neato, not to protect your eyes.
Warm the glass up in your hands for a while, then try it again.
The other day I was rummaging through some junk in the garage and down came my prototype for a laser pistol, built with a 7" tube and miniature "James Bond" PS. It's in a PVC pipe enclosure, and the glass didn't break, but I'm afraid to try it out. I don't think I've fired it up in maybe 10 years.
So yesterday I get an email encouraging me to "stock up on more" laser diodes. Ever since then, I've been pondering what a person could possibly do with a few hundred schlocky laser diodes.
If there were some appropriately cheap way to modulate the beam, they might provide secure point-to-point communication (I mean some much faster way than just OOK of the diode itself).
Perhaps a spinning mirror could be illuminated by a stack of a few hundred laser diodes. This could then be used to display text or designs on a wall.
Anyway, it makes me wonder if this eBay vendor is nuts, or are there great uses for large quantities of laser diodes that I'm just not seeing? I'd love to come up with some killer use.
I question the sanity of anyone who buys 10 lasers in the first place:)
I do like the spinning idea. I was thinking about this but small scale. One could imagine 8 or 16 or whatever number of these lasers rotated themselves or reflected from a rotating mirror. Would make a dead simple text display projector. Without the complication of a second rotating mirror and having to get in sync'ed up. With the bonus of all that extra brightness.
Now, a Propeller has 32 I/O pins. Two used for serial comms and two for the EEPROM and one for a sync input leaves enough to drive 27 lasers very easily.
I think I have to get myself some lasers....
Or prices drop more. Every hoarder's nightmare.
Buy low, sell high!
You do need to be careful about any activities that may appear like price gouging in a time of shortage....most states have laws against that. We need to study the business models of the oil companies to see how that works most effectively and apparently legally.
j/k - I don't have the slightest clue about the gasoline industry
Peter demonstrated just such a thing late at night at one of the Expos at Parallax (remember when they did that?), he used a solar cell as the collector and was able to transmit audio quite well. I would not have guessed that a solar cell could respond so quickly.
Something else you could do, create an array to make a projectable dot matrix display.
Are they going to start paying us to take them off their hands? Have we turned into a waste disposal system for China?
I'll build up an S6986 laser sensor with one and report back in few days. Something even bigger is afoot... I can say no more.
We'll this comes to mind, am I close?
http://www.youtube.com/watch?v=Ei_GZnrr1nw
C.W.
I won the county science fair in 11th grade with my "Light Beam Communication" project. I build several things (don't EVEN ask how I sent a dollar bill over a light beam); among them was a "Photophone" first invented by Alexander Graham Bell. You talked over a sunbeam! The "microphone" was just a tube with a very thin glass mirror at the end, shiny side out, mounted on a tripod for stability. The thin mirror flexed concave & convex when you spoke into the tube, and thus the reflected sunlight beam was amplitude modulated. The receiver was a concave mirror focused onto a solar cell, which output directly into an audio amplifier. Simple but effective.
http://en.wikipedia.org/wiki/Photophone
Dangerously close, my friend!
No fusion has been achieved, yet, but otherwise the diodes that arrived today have been most impressive.
They cost so little and work so well that they beg to be part of something epic. I like the ideas mentioned. Some form of projection clock is clearly forthcoming. On New Years it could even project onto a public structure for the final countdown.
10 points to Gryffindor Heater for his wry wit!
Today I find this article which states otherwise: http://www.repairfaq.org/sam/laserdio.htm#diobcc4
"...this general rule appears not to apply for all laser diodes including those in many common diode laser modules and even cheap ($9.95) laser pointers. These are now being used routinely for experiments in interferometry and even holography...coherence lengths of 20 cm or more are not unusual. This is similar to that of a typical helium-neon laser..."
I guess Gordon is right that these elcheapo lasers may not cut it but looks like holography with laser diodes is not out of the question.
Most of us use it with sensor here:
http://forums.parallax.com/showthread.php/149770-7-Laser-Sensor-Bulk-Buy?highlight=%247.00+Laser+Sensors
Just monitor the pin on the sensor. BS2 Propeller, whatever. See post #1 for links for connections. It's self modulating.
I quickly found this page:
http://www.designerinlight.com/holo/laser.htm
written by a couple of guys that experimented with diode lasers to make holograms, and what they needed to do in order to stabilize the output, including a water-cooled heat sink and a fairly pricey constant current driver. It's not easy to make a hologram with a laser that's changing its frequency maybe dozens of times a second. Can't imagine these diodes not drifting all over the road.
An interesting experiment that would demonstrate how stable the output is would be to make a simple beam splitter interferometer, and point both beams into a phototransistor. Connect it to an amp, and listen to the frequencies beat against one another. A HeNe on a stable solid platform will exhibit relatively little variance. That's what you need for a good hologram. You'll hear the output change if you waft air in front of the detector. The wilder the sound, the more blurry the hologram is likely to be.
Sorry to hear that!
I was hoping to get mine today but no luck!
Maybe Monday...
-Phil
Well I've made a controller for work that can has less than 3uAp-p noise on drive current and 0.3mKp-p temperature noise with a butterfly package DFB laser diode. The critical circuits are about $100 in parts all controlled by a Propeller. (could likely get that down to $50 with a re-design if I had to) From various tests, I'm pretty sure that laser has a bandwidth of ~1MHz using this controller. The hard bit with diode lasers is the temperature stability needed. 1mK or less is just TINY. When playing with the thermistor circuits, I could tell if the room lights had switched on/off just by looking at the temperature readings... The worst bits though are temperature gradients compounded by the mismatched coupling between ambient temperature, the feedback thermistor and the laser diode. (oh, and the solder used in thermoelectric coolers creeps as well)
If I was looking for narrow line width at low cost, I'd build an external cavity diode laser with a cheap single mode diode. (I.e.like the link from my first post.) Even without any stabilization, an external cavity diode laser should drift into periods of <1KHz line width. Probably pretty easy to see when the laser is "happy" with a photo-diode and oscilloscope. Anybody going to try that with the 21 cent laser and a dime-store diffraction grating?
Marty.
Phew! If PhiPi's happy, I'm happy.
I'll make a hoarder out of you yet.