Note: Photos of Hewlett Packard and Perkin Elmer HeNe lasers have moved to their own wings of the gallery.
(The following photo provided courtesy of: Curt Graber (cgraber@fwi.com).)
(The following photo provided courtesy of: joerut (joerut@epix.net).)
(The following photo provided courtesy of: Jeff Thomas (jthomas@amug.org).)
(The following 2 photos provided courtesy of: Wes Ellison (ellison@falcon.cc.ukans.edu).)
(The following photo provided courtesy of: Steve Thatcher (fizzbin@worldnet.att.net).)
(The following 2 photos provided courtesy of: Daniel Ames (dlames2@aol.com).)
(The following photo provided courtesy of: Dave (Ws407c@aol.com).)
(The following 2 photos provided courtesy of: Don Noonan (don.noonan@powernetworks.com).)
This is a HeNe tube with a green output at 543.5 nm, And, you thought all HeNe lasers were red, huh? :) It must be different due to the color of the bubble wrap. ;-)
(The following photo provided courtesy of: Keith (kee@asu.edu).)
Here are three more 'other color' HeNe tubes. The top one is a Hughes style yellow (594.5 nm) tube, the middle one is also supposed to be a yellow HeNe laser tube but this sample produces some orange (604.6 nm) as well, and the bottom one is a green (543.5 nm) tube which also has a built-in three-screw mirror adjuster on its OC.
This is a really cute little demonstration see-through HeNe laser. It is Scientific Laser Corporation model SLC.8MWCLR.
(These 3 photos provided courtesy of: Darrel Grubbs (dgrubbs@netdoor.com).)
Bell Labs developed and produced some number and variety of portable demonstrators to promote the idea of optical communications. At least some of these had an actual working HeNe laser based on a two-Brewster laser tube with external mirrors in adjustable mounts, and power supply in a self-contained unit with orange Plexiglas cover over the tube. Some included a modulator with a separate receiver based on a solar cell. These demonstrators came packed in a handy traveling salesman's type sample case. :)
I don't know for sure if all of these had working lasers. (The one in the next section is definitely fake, but could easily fool a non-laser geek type.) But, now I do have the remains of one of the laser-only units, so that confirms the presence of real lasers in at least some models. The tube is broken but it indeed was a complete working HeNe laser at one time. The external mirrors look pristine, which is probably just as well since they are likely soft-coated and cannot be cleaned. The mirror mounts are, well, funky. The mirrors are attached to a spring flexure with three screws with tapered ends (user accessible!) entering from the mount's edge at the 12, 4, and 8 o'clock positions. I have little doubt that if I mounted almost any two-Brewster HeNe laser tube between the mirrors, it would lase. I may do just that someday, at least as a test. Of course, if someone wanted to donate or build a an historically authentic HeNe laser tube to go in there, that would be even better. :) I couldn't find any dates on the unit but it must be quite old.
The power supply for the HeNe laser tube is very simple - just a high voltage transformer (about 3,000 VRMS) feeding a bridge rectifier consisting of 4 series pairs of 426J-263 diodes (whatever they are) with a single 0.1 uF, 4 kV capacitor and a series pair of 4.64M ohm bleeder resistors across its output. The ballast is a 75K ohm 25 W resistor and there is a current meter in the negative return. Although it reads 50 mA full scale, the ballast resistor would have turned to smoke long before this current was reached - just over 18 mA would result in 25 W dissipation in the resistor. Given the relatively small diameter of the bore (about 2 mm), 10 or 15 mA would probably be the normal operating current. Since there is no adjustment for tube current, it's not clear why a meter is needed at all. If the tube lights up, it's operating correctly, go fiddle with the mirror adjustments if there is no laser beam! :) The 0.1 uF capacitor doesn't really provide much smoothing, so the result is closer to pulsed DC at 120 Hz. Thus the tube must restart on every half cycle. (There is a wire wrapped around the bore connected to the positive lead, presumably to help this. Here's the circuit diagram:
D1 D2 75K 25W
T1 +--+---|>|---|>|------+------+----+----/\/\----+--+
||( | | | | | |Tube+
||( +---|<|---|<|---+ | | / |.-|-.
||( D3 D4 | | | \ 4.64M || |
||( | | | / || |
||( T1: 3kV | | _|_ \ || | LT1
||( D1-D8: 426J-263 | | C1 --- | || |
||( | | .1 uF| \ || |
||( | | 4 kV| / 4.64M |||_||
||( D5 D6 | | | \ '-|-'
+--+---|>|---|>|---|--+ | / M1 |Tube-
| D7 D8 | | | - +-----+ + |
+---|<|---|<|---+---------+----+----|50 mA|----+
+-----+
The primary-side components not shown consist of the fuse, power switch, and power indicator neon lamp.
Note that there is no actual indication on the thing I have that it is from Bell Labs so I'm making an assumption based on its similarity to the one below.
When I first acquired the photos of the demonstrator in the Gallery, I had doubts as to whether it actually had a working laser or just a cool-looking neon sign-type tube for show - and actually did the communications with a separate conventional modulated lamp (an arc lamp is mentioned in the description below and its presence doesn't make much sense otherwise). The ends of the tube are not clear in any of the photos and the bore looks too wide to be part of a functional HeNe laser tube. In addition, the mirrors look suspiciously clear but perhaps they are just missing on this unit. But the access holes in the Plexiglas cover for adjusting the mirrors that are present on mine are not visible on this one.
However, for what follows, I originally assumed it to be a real laser - else I couldn't have included it in the "Assorted Helium-Neon Lasers" wing of the gallery! :) However it isn't. ;(
(The first 8 photos and the following description (the three paragraphs) provided courtesy of: Rick Carpenter (Fiesta1043@aol.com).)
This is a true collectors' item. It is a laser beam demonstrator kit used to show the future of communications via laser optics. Here is the story. This unit was rescued from the trash years ago at a Southern Bell office by my brother in law who is a retired telecommunications engineer for the phone company. This unit was used in community relations programs as a demonstrator unit to show how telephone signals could travel over laser light. We believe it is vintage 60's judging form the tube circuits and the original carrying case.
The unit measures 20" long and has an amber colored Plexiglas cover over the laser tube. The only markings are 3 kV which resembles some of the vintage Western Electric stamps. At one end is access to a concentrated arc lamp, (Sylvania A2/T, a spare one is included in the case, just in case). The telephone hand set was plugged into the unit and the receiver of the beam is the small black cylindrical object seen in the photos. In the cylinder is a photocell like surface with wires that would probably connect to an amplifier and telephone receiver to get the signals on the other end.
The demonstrator is packed in a Salesman's sample-like carrying case (genuine fiberboard construction!) along with 4 spare vacuum tubes (for the modulater?), fuses, telephone handset, and the optical receiver.
The following two photos of another sample from Bob Hess:
This one is definitely fake, but could make a decent prop for a futuristic movie (at least in the 1960s). It consists of a neon sign-type tube with red coated glass mounted in a nicely machined aluminum assembly that might have been for a real laser at some point. At one end is a tiny incandescent flashlight lamp - no LEDs in those days! The modern version would use a diode laser module! A red plastic filter and glass lens produces a reasonable facsimile of a poorly collimated beam. But as you'll see in the photo of the unit in operation, it sort of looks like a laser beam spot. There is also a pair of glass lenses at the other end that appear to serve no useful purpose other than filling the holes in the aluminum structure, which for some inexplicable reason, is cut away.
The neon tube could probably run on a HeNe laser power supply (though not very brightly), but I found a small neon sign transformer (3500 V) that works fine. It glows a gorgeous deep red for which the digital photo does not do justice. The beam bulb runs on 3 V.
It is not known whether this is a one-of-a-kind or was replicated like the traveling salemans' laser demonstrator kit.
(These 5 photos provided courtesy of: Mark Buckles (markbkls@cts.com).)
This is a set of older Aerotech self contained HeNe lasers, probably around 2 to 3 mW (by the size and model number, despite what the CDRH sticker says about Class IIIb and 25 mW max!). They date from 1980 and thus I am impressed that they work at all. However, apparently after a few minutes, they start flickering indicating a tube pressure problem (probably high from leakage of the soft-seal mirrors).
Dr. Narinder Kapany founded Optics Technology, Inc. in 1960 and was Chairman of the Board, President, and Director of Research until 1972. The company made lasers and fiber optic assemblies for a wide range of specialties, and is still in business. One of Dr. Kapany's hobbies is sculpture, which may explain the extravagant industrial design which went into the case of the Model 170 laser.
(These 8 photos and the following description provided courtesy of: Lisa Ledger (pontiac1@jps.net).)
I was going to list this with the statement "Cutting Edge Technology" until I realized the pun. This was a true state of the art piece of equipment from the early 1970's. It came from the estate of a NASA engineer. It was made by Optics Technology Inc., out of Palo Alto, California.
I wasn't sure of exactly what I had, but luckily I live down the street from a high tech laser company whose engineers were more than happy to take a look at this. Once they had the top off, this drew them like bees to honey! This laser has an elaborate glass tube with Epoxy seals and of course, after all this time, the gasses have all leaked out/air has leaked in, whatever. The engineers thought it may have generated a 3 mW beam and showed me the present day equivalent, which was about the size of a very long pencil. They finally proclaimed this as an extremely interesting relic!
This is a vintage external mirror HeNe laser with a relatively wide bore and a heated filament-cathode. The Americal Optical Corporation model 3100 HeNe laser is probably made by Gaertner as their name also appears on the sample I have. The AO-3100 is (described in the chapter: Helium-Neon Lasers of Sam's Laser FAQ (section: "A Really Old HeNe Laser").
These five photos show the details of two dead units.
(The following photo provided courtesy of: Lance Ward (lance@acd.net).)
(The following four photos provided courtesy of: Gene S. Berkowitz (gene.berkowitz@comcast.net).)
These 7 photos are of a working sample I now have. It was contributed by Phil Bergeron at the USF Physics lecture - Demonstration Facility, Tampa, FL. Thanks Phil! :)
The color rendition of my digital camera isn't very good. The color in the main bore and larger sections of tubing actual should look close to that in normal HeNe lasers. But the cathode glow (the bright blob) is actually more yellow (though not qutie the yellow in these photos). :)
(The following seven photos and description provided courtesy of kepsalesantiques.)
The Electro Optics Associates (EOA) Model LAS-101 was intended for the educational market. It is a portable laser designed for use with a user-provided power supply, and it features a double-walled plasma tube for extended lifetime, an internal resonator structure and a stylish green Plexiglas cover. EOA was a Palo Alto, Calif.-based company that dissolved in the mid-1970s.
Specifications:
The EOA model LAS-101 included a booklet called "Laboratory Experiments with Coherent Light" to help science educators explain the new technology to students.
This is an example of a very early Helium-Neon gas laser built for portability and general lab use. The laser was powered by a user-supplied 300VDC 60mA lab power supply, gave 0.5 mW single mode, and cost $660 new.
The slight burn mark on the bottom of the case may be indicative of a problem with the laser unit. :)
