Each of the chapters that follow are dedicated to one particular type of home-built laser. For most, it is one of those presented in Scientific American which is first summarized, followed by any non-SciAm designs, and other related information. There may also be other projects specifically related to each type of laser. Some of these (like the ones on the HeNe laser in particular), may require much less custom work by using more off-the-shelf new or surplus parts and are thus alternatives to diving into a fully home-built design.
Note that the ORDER of the first 7 of the following chapters is based on the sequence in which these lasers were presented in Scientific American and does NOT reflect their level of difficulty! For that, please see the comments starting in the section: Which Laser to Build? and the more specific information in each chapter.
In the chapter for each type of home-built laser, information directly related to the relevant SciAm laser (where applicable) will be presented roughly as follows (not all of these items will be present for every laser):
The format of the laser specifications will follow the general outline given below. (Since most of these are gas lasers many of the entries will be missing for the dye laser and solid state lasers.)
The following notation will be used to denote input and output connections:
Duplicating (or improving on) a known commercial design rather than one from a 20+ year old article could very well result in higher efficiency and output power and better beam quality. See the section: Sam's Three Part Process for Getting Your Feet Wet in Gas Lasers for one possible approach to this.
(From: Flavio Spedalieri (fspedalieri@nightlase.com.au).)
My opinion and that of many other laser experimenters is that the home construction of Ar/Krypton and HeNe lasers, requires much more critical control, and generally it may lead to a laser that will never produce a beam (but the educational experience is very valuable).
Also, Argon and Helium Neon lasers are very cheap, and quite common, so when you compare the construction of these lasers with the purchasing them from surplus market, its more cost effective to just purchase a commercial argon ion or HeNe laser tube (and build your own resonator and power supply if you like).
I would suggest building a laser that is not as readily available, and the cost of such systems are very high - it's a great feeling to have built a laser that is worth tens of thousands of dollars, yet only have spent a few hundred dollars.
The lasers that are a good for construction are:
However, there are enough differences that for most of these home-built lasers, it doesn't make sense to do this. Even between, say the HeNe and Ar/Kr ion lasers, the Brewster angle and bore diameters differ somewhat. The CO2 laser uses a wide bore and internal mirrors while the HeHg uses a wide bore but external mirrors. The electrode requirements differ as well. Finally, some of the materials - like mercury - will contaminate the glass and metal parts of the tube and vacuum system so attempting to reuse a tube with a different gas-fill may be counterproductive. However, if you really want to try it, see the section: Comments on a Universal Experimenter's Gas Laser.
Here are some additional comments specifically for the CO2 laser versus the others:
(From: Flavio Spedalieri (fspedalieri@nightlase.com.au).)
Unfortunately, it is not possible to use the same tube for the CO2 and HeNe or argon/krypton ion lasers:
Where possible, an attempt will be made to estimate the expected power (or at least an upper bound) based on tube dimensions, power supply, and other factors. At best this will be a wild guess but may provide some indication of the possibilities for improvement by tweaking the design.
Note that this also means that it is NOT possible to determine the laser safety classification for these lasers. They maybe of very low power but this is not guaranteed. So, treat their output as at least Class IIIb (Class IV for the CO2 laser) until you can be sure that it isn't!
I would definitely recommend the HeNe over the argon ion laser tube as it is a lot easier and cheaper to build or buy a suitable power supply - and somewhat safer as well. Somehow, working around high voltage but low current of a HeNe laser just seems to me to be much less scary than being in close proximity to the non-isolated AC line voltage at many amps (and killer fan) of an ion laser!
A little searching of the laser surplus places should turn up an inexpensive HeNe laser tube of this type (you may have to ask explicitly - they never seem to be in the catalogs but usually lurk on a forgotten shelf in a rear storage room on the second level sub-basement. :)
See the sections starting with: The Half-Way Approach for a Home-Built HeNe Laser and A One-Brewster HeNe Laser Tube.
There are other alternatives in between this approach and a full-blown from beach sand up laser project. See the additional information in the chapters on the home-built HeNe and Ar/Kr ion lasers.
Solid state lasers are inherently of the "half-way approach" type since you can't grow, shape, grind, and polish your own laser crystals; or build flashlamps or laser diodes. Yet, they have many attractive qualities. Pulsed SS lasers can generate the highest pulsed power of any home-built laser and diode pumped SS lasers have the ability to generate high green CW power. Parts are becoming more readily available at attractive prices and with reasonable precautions and awareness of the safety issues, the risks are relatively low and the chances of a successful outcome are quite high.
Here is a list of some of the laser articles that have been published in the Amateur Scientist columns of Scientific American. The first 7 of these constitute the chapters on laser construction found in "Light and its Uses":
Except for the one in (6) which for all practical purposes you can ignore, all the others are built from the ground up using basic materials like glass tubing, pieces of plastic and metal, mirrors and other optics, glue, duct tape, various bottled gases and other chemical supplies, high voltage transformers, resistors, capacitors, diodes, wire, etc., along with blood, sweat, and possibly some tears. :) (The article in (6) deals with driving a long obsolete type of IR laser diode which had limited applications. However, modern equivalents do still exist. See the section: And Those High Power Pulsed Laser Diodes? if interested.)
In addition to actual laser construction, there have also been related articles on vacuum systems, glass working, and other laser related subjects, particularly during the initial laser craze of the 1960s and 1970s but extending to the present particularly for more exotic types of lasers and laser applications including holography and interferometry.
As an aside, I lament the fact that few of the more recent Amateur Scientist columns have nearly as much sophistication and depth as those from that era. On the other hand, experiments that are presented may be performed by nearly anyone who is reasonably handy using parts from the local home center and Radio Shack and yet this is definitely real science. There is no need for high vacuum systems, glass working skills, strange gas mixtures and other chemicals, or fancy test equipment!
A large public or university library will likely have all of these somewhere though you may have to request them from their storage vaults and/or they may be on microfilm or microfiche. While the Scientific American Web site has many interesting articles, they do not go far enough back to be of much use for laser construction. For possible Web access, see the section: On-Line Access to the Scientific American Laser Articles.
Specifically for laser construction and optics articles, see the sections: Light and its Uses - Complete Table of Contents. However, the more general indexes may be more useful since they also list project articles in related fields like vacuum systems and electronics. The book "Light and its Uses" is long out of print but your library may have this as well (in its ancient not-that-popular books collection!). It may also be possible to obtain a copy from a dealer in used scientific books. Although Internet companies like Amazon.com offer to attempt to find such books, going to a more specialized search site like: Bibliofind (which appears to be owned by Amazon.com now) may be more productive. They claim to have access to "ten million used and rare books, periodicals and ephemera offered for sale by thousands of booksellers around the world". I have heard of this being a successful means of obtaining "Light and its Uses".
This appears to be the only source for an electronic version of the Amateur Scientist articles at the present time. There were a couple of others but they have disappeared. Of course, you could go to a real library. What a concept? :)
LIGHT AND ITS USES:
THE AMATEUR SCIENTIST
Readings from: SCIENTIFIC AMERICAN
Introductions by: Jearl Walker, Cleveland State University
Publisher: W. H. Freeman and Company, San Francisco
CONTENTSI. LASERS
Introduction 3
1. Helium-Neon Laser (Sep, 1964) 7 A helium-neon laser built in the home by an amateur
2. More on the Helium-Neon Laser (Dec, 1965) 14 Increasing the life of the amplifier tube at modest cost NOTE ON CLEANING THE MIRRORS 17
3. Argon Ion Laser (Feb, 1969) 18 An argon gas laser with outputs at several wavelengths
4. Tunable Dye Laser (Feb, 1970) 24 An inexpensive tunable laser made at home using organic dye NOTE ON THE POWER CIRCUIT 29 April 1970
5. Carbon Dioxide Laser (Sep, 1971) 30 A carbon dioxide laser constructed by a high school student
6. Infrared Diode Laser (Mar, 1973) 35 A solid-state laser made from semiconducting materials
7. Nitrogen Laser (Jun, 1974) 40 An unusual gas laser that puts out pulses in the ultraviolet NOTE ON EXTRACTING NITROGEN FROM AIR (Oct, 1974) 44
II. HOLOGRAMS
Introduction 46
8. Homemade Hologram (Feb, 1967) 43 Experimenting with homemade and ready-made holograms
9. Stability of the Apparatus (Jul, 1971) 55 Insuring a good hologram by controlling vibration and exposure
10. Holograms with Sound and Radio Waves (Nov, 1972) 57 Sound and radio waves recorded on film by a precooling process
III. INTERFEROMETERS
Introduction 61
11. Michelson Interferometer (Nov, 1956) 66 A homemade instrument that can measure a light wave
12. Cyclic Interferometer (Feb, 1973) 70 An interferometer constructed from plate glass and lenses
13. Speckle Interferometer (Feb, 1972) 72 A laser interferometer that can measure displacement 14. Series Interferometer (June, 1964) 76 A series interferometer to observe various subtle phenomena
15. Interferometer to Measure Velocity (Dec, 1965) 81 A laser interferometer that converts a velocity to a sound signal
16. Interferometer to Measure Dirt Content of Water (Jun, 1973) 82 A laser beam and a photocell to measure the dirt content of water IV. INSTRUMENTS OF DISPERSION
Introduction 88
17. Ocular Spectroscope (Dec, 1952) 90 A spectroscope for a telescope that separates colors in starlight
18. Bunsen Spectroscope (Jun, 1955) 92 Reconstructing the spectroscope that initiated modern spectroscopy NOTE ON MAKING LIQUID PRISMS (Apr, 1956) 95
19. Diffraction-Grating Spectrograph (Sep, 1956) 96 An inexpensive diffraction-grating spectrograph
20. Diffraction-Grating Spectrograph to Observe Auroras (Jan, 1961) 102 Auroral spectra made as part of the International Geophysical Year
21. Inexpensive Diffraction-Grating Spectrograph (Sep, 1966) 106 A spectrograph with the grating mounted on a concave mirror NOTE ON THE GRATING (Nov, 1966) 111
22. Ultraviolet Spectrograph (Oct, 1968) 112 A spectrograph with a quartz prism for work in the ultraviolet
23. Inexpensive Spectrophotometer (May, 1968) 118 A photocell to measure the intensity of color transmitted by a liquid
24. Recording Spectrophotometer (Jan, 1975) 124 A recording spectrophotometer built by a high school student
25. Spectroheliograph (Apr, 1958) 131 A spectroheliograph to observe details on the disk of the sun
26. Spectrohelioscope (Mar, 1974) 136 A new kind of spectrohelioscope to observe solar prominences Bibliographies 143
Index 145