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    Home-Built Laser Types, Information, and Links

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    Introduction to Descriptions and Designs of Home-Built Lasers

    What is in this Chapter?

    Having survived a discussion of lab/workshop safety and requirements, vacuum systems, glass working, optics, and power supplies, it is now time to look into the detailed features and characteristics of the types of the lasers that are possible to construct at home. This chapter is a sort of introduction to the detailed chapters on each of the lasers that follow. In addition, there are some comments later on that may be of help in deciding which home-built laser to tackle first (or second or third). At the end of this chapter is information on the Scientific American (SciAm) laser articles including the collection: "Light and its Uses" and possible on-line access to this valuable resource.

    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):

    1. Introduction and general description.

    2. Specific laser output, electrical, and other safety information.

    3. Links to relevant Web sites with additional information including some that offer kits, plans, or even completed lasers (don't whimp out on me!).

    4. Photos or links to photos of completed home-built lasers.

    5. Diagrams showing major mechanical and electronic assemblies of typical home-built lasers.

    6. Summary of the major optical, physical, and electrical, characteristics and requirements, including an estimated 'level of difficulty' profile. See the section: Home-Built Laser Description.

    7. Sources for parts and supplies relevant to each particular type of home-built laser.

    8. Guidelines for improving the chances of a successful outcome for construction of those lasers that are finicky about their design or fabrication and which shouldn't be modified (except as noted) until the basic version is happily lasing.

    9. Any errata, suggestions, improvements, or other information that might simplify construction, alignment, enhance reliability, or boost power output, as well as identifying any special safety considerations.

    10. Email correspondance with those who have attempted their construction possibly including additional complete laser descriptions as in (4), above.

    11. Articles, newsgroup, and discussion group postings relating to the particular type of home-built laser.
    Where the same type of laser (e.g., HeNe, Ar/Kr ion, CO2) is covered in Part III of this document, those chapters should be read FIRST since the basic characteristics and principles of operation are described there.

    Home-Built Laser Description

    Each of the following chapters include a description of the corresponding laser from the Amateur Scientist article of Scientific American (or the collection "Light and its Uses") if one exists. This will include a somewhat standardized summary of the most important physical, electrical, and optical characteristics of the laser including the resonator, and necessary power supply, and vacuum system or other special requirements. An estimate of the required skills and level of difficulty for each will also be provided.

    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 beauty of a home-built laser is that there is no law that says you cannot experiment with virtually all of these specifications. If you want to build a HeNe laser with a longer or narrower bore or with a large 'can' style cold cathode instead of a neon sign electrode - go for it! Boosting power output, in particular, may be quite viable especially for the pulsed lasers like the Ar ion and CuCl/CuBr with a more sophisticated power supply and additional (e.g., water) cooling.

    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.

    Which Laser to Build?

    A variety of factors should be considered in determining which of the many possible lasers to undertake. In addition to difficulty, there are other personal factors such as the desire for a visible CW or pulsed beam or high enough power to be used for wood or metal working (e.g., CO2 or ruby/Nd:YAG).

    (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:

    These are just some of the possible lasers that can be built by the dedicated laser experimenter.

    Can I Use the Same Tube for Multiple Home-Built Lasers?

    There is a great amount of similarity between some of the home-built lasers described in subsequent chapters as well as with variations on these which aren't dealt with explicitly (e.g., HeHg and HeCd).

    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:

    Also these lasers are much more critical in the following areas:

    Estimate of Home-Built Laser Output Power

    None of the articles in "Light and its Uses" ever list the output power of the home-built lasers. This isn't surprising given the era (1960s for this one) and even the present high cost of laser power meters (see the section: What Makes a Laser Power Meter So Expensive?.

    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!

    So, Maybe Constructing a Laser from Basic Elements Isn't for You?

    If you're still not sure which laser to build - or whether building a laser from scratch is for you at all, consider using a commercial HeNe or argon ion tube with one or two Brewster windows and constructing a resonator including mirror mounts. This will give you a feel as to whether dealing with metalworking and precision optics is something you enjoy without having to invest in a vacuum system, and obtain weird gases and other supplies. The power supply can be built or bought as desired. You will still have to fight with mirror alignment and can gain access to the inside of the laser cavity for experiments And, perhaps most important, you can really impress your friends with a way-cool high-tech looking laser. :)

    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.



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    Scientific American Articles on Lasers and Related Topics

    The laser construction articles from the Scientific American "Amateur Scientist" columns (most of which were subsequently reprinted in the collection "Light and its Uses") still represent the best source of information of its type available to the hobbyist and experimenter. While research and technical papers may exist on these topics, access to them is often non-existent to common people and/or they are written at such a level as to be of minimal value to anyone who isn't an expert in the field.

    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":

    1. Helium-Neon Laser, September, 1964, pg. 227.
    2. More on the Helium-Neon Laser, December, 1965, pg. 106.
    3. Argon Ion Laser, February, 1969, pg. 118.
    4. Tunable Dye Laser, February, 1970, pg. 116.
    5. Carbon Dioxide Laser, September, 1971, pg. 218.
    6. Infrared Diode Laser, March, 1973, pg. 114.
    7. Nitrogen Laser, June, 1974, pg. 122.
    8. Mercury-Vapor Ion Laser, October, 1980, pg. 204.
    9. Copper Chloride Laser, April, 1990, pg. 114.

    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".

    On-Line Access to the Scientific American Laser Articles

    In the age of electronic access, it would obviously be desirable to be able to browse articles from Scientific American on-line. 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 and apparently have little interest in out-of-print material. I have attempted to obtain permission from Scientific American to provide the chapters on laser construction in "Light and its Uses" on-line. Unfortunately, the editors of Scientific American have denied my request. I had even offered to scan and OCR the originals and have Scientific American maintain the resulting documents SOLELY at THEIR Web site - yet they still refused! "For policy reasons", they said. Probably too many lawyers :-(. Since I will not knowingly violate someone else's copyright, that's as far as it goes - here. Sorry.

    However in 2013, Dr. Shawn's The Amateur Scientist 3.0 has all the Amateur Scientist articles on-line. While not in original form, all the information is there and the diagrams are of adequate quality. I assume they have copyright permission since it seems to be a fairly well developed Website, but who knows? Get 'em while you can! This may have been acquired after the apparent demise of the Society for Amateur Scientists, whose URL now points to something else.

    CDROM with the SciAm Amateur Scientist Archive

    The complete 72 year run of the Amateur Scientist column including everything in Light and its Uses is available on CDROM from a variety of sources including Amazon, Scientific American "The Amateur Scientist" from Science Academy Software, and Surplus Shed. In 2013, it is a whopping $29. While individual articles may be downloaded from the Website, above, having the entire collection in one clump of bits has its merits. :-)

    Light and its Uses - Complete Table of Contents

    Even after more than 20 years, "Light and its Uses" is considered to be THE reference for amateur laser construction. However, it is easy to overlook the many other excellent projects contained in this work. They are probably of even more value overall because fabrication of most of the optical instruments is less demanding in some ways than the lasers since no vacuums, or messy or toxic chemicals are required and light sources and readily available low cost lasers other than those from the construction articles can be used.

    LIGHT AND ITS USES:

  • MAKING AND USING LASERS
  • HOLOGRAMS
  • INTERFEROMETERS
  • INSTRUMENTS OF DISPERSION

    THE AMATEUR SCIENTIST

    Readings from: SCIENTIFIC AMERICAN

    Introductions by: Jearl Walker, Cleveland State University

    Publisher: W. H. Freeman and Company, San Francisco

     
    CONTENTS
    

    I. 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



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    Sam's Laser FAQ, Copyright © 1994-2017, Samuel M. Goldwasser, All Rights Reserved.
    I may be contacted via the
    Sci.Electronics.Repair FAQ Email Links Page.