<==== Sam's Laser FAQ ====>


Safety, Info, Links, Parts, Types, Drive, Construction

A Practical Guide to Lasers for Experimenters and Hobbyists
Version 19.80 (17-Oct-19))

Copyright © 1994-2022
Samuel M. Goldwasser

--- All Rights Reserved ---

For contact info, please see the Sci.Electronics.Repair FAQ Email Links Page.

Reproduction of this document in whole or in part is permitted if both of the following conditions are satisfied:
  1. This notice is included in its entirety at the beginning.
  2. There is no charge except to cover the costs of copying.

Sam's Laser FAQ Welcome Page

Sub-Table of Contents

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    Welcome to Sam's Laser FAQ!

    This collection of documents, called "Sam's Laser FAQ", has a truly immense amount of practical information on a variety of laser related topics. If you are already familiar with its scope, purpose, and general organization, go directly to Sam's Laser FAQ Table of Contents. However, if this is your first visit - or you have been away for awhile - check out the summary and version update info below.

    Sam's Laser FAQ provides a wealth of useful (not just textbook) information on many types of lasers of interest to the experimenter and hobbyist including:

    Sam's Laser FAQ was developed to provide a unique resource for experimenters and hobbyists - as well as just plain old basement tinkerers. To the best of my knowledge, nothing as comprehensive has ever been available anywhere else in the explored universe (and almost certainly beyond).

    If this was what you were looking for, your search is over! :-)

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    A Word About These Pages

    Sam's Laser FAQ is declared to be a fluff-free zone! There will be no unnecessary, superfluous, or useless graphics of any kind - including but not limited to: dancing, gyrating, or other animated icons, colored textured backgrounds that are impossible to read through, or forced downloading of bit intense pictures that may be of no interest to you. Nor, will I ever expect you to use a particular brand of Web browser to be able to effectively access these pages. There are and never will be any advertisements, cookies, or other impositions on your time and space. In the time that it may take wading through a single monstrosity of the professional Web page designers at other sites, you will be able to find out what you want to know, when you want to know it! What a concept. :-) (Note, however, that your browser needs to be configured properly to make sense of the many ASCII diagrams, schematics, and tables. See the document: Suggested Browser Settings for font and other related information.)

    In return for this gold mine of information, please make a serious effort to find the answers to your questions before contacting me. It may take just a wee bit of effort and could stress a few neurons in the process, but there is an excellent chance that what you seek is covered here. Should you be really stuck - or just want to discuss lasers, I will respond to email in a timely manner. However, if your questions indicate that you haven't even gotten past the Welcome Page, AND I am in a good mood, you will get a somewhat polite reply to read the appropriate chapter(s) of the FAQ. On the other hand, if it is a bad day, and you are really really lucky, you will probably be ignored. Don't get me wrong - I enjoy discussing lasers with laser enthusiasts and novices alike, and will be happy to do so at almost any hour of the day or night. However, if you're seeking some basic information, I would really really appreciate it if you do at least a bit of your homework first. In any case, if you do email me, I expect to be able to hit the reply key for my mail program and not get bounced email. I will not attempt to unjumble any anti-SPAM email addresses! I have posted over 20,000 articles to the USENET newsgroups using my true email address. And, you won't pick up SPAM via my private email anyhow. Even computer viruses avoid my address book since it's on a unix system!) Yes, SPAM is a pain but I tolerate the small amount I get resulting from postings so others will not be inconvenienced.

    However, due to the increasing amount of SPAM via repairfaq.org email addresses, I have decided to require all initial email contact from the FAQs to be via the Feedback Form on the Sci.Electronics.Repair FAQ Email Links Page. (At some point my repairfaq.org email address will cease to function.) Any reply from me will have a valid email address to use for future correspondance. My apologies but I've already made so many millions from all those get rich quick schemes that I've run out of places to put it all. :)

    Note: I NEVER send email attachments without prior contact. If you receive an unsolicited message supposedly from one of my addresses with any sort of attachment, it is bogus and possibly a virus - someone's address book includes my address and their computer is infected. Send me the complete headers and I'll attempt to check it or just hit the delete key.

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    A Somewhat Polite Gripe About Professional Web Sites

    One of the most time consuming and annoying parts of maintaining the Sci.Electronics.Repair FAQ and Sam's Laser FAQ is attempting to keep the outside links up to date. Why does it seem that most professional Web site designers are programmed by their genes to rework the directory structure of their Web sites every 26 microseconds??? Isn't this totally counterproductive from a business point of view? Links that people have painstakingly set up stop working with "Error 404" or "Server not Found" and no hint of where they went or often if the company even still exists. So countless person millenia are wasted attempting to relocate them? How many just give up and take their business elsewhere? Does it really make sense to annoy your customers?

    Granted, personal Web sites that move from one ISP to another due to lower costs or whatever may not have the luxury of being able to retain forwarding links. But businesses and organizations should not have this issue.

    In all fairness, there are a few - but very few compared to what's out there - who do either provide direct forwarding links, or at least attempt to redirect to an appropriate Web page. However, the vast majority would seem to take the attitude that the Web site is there to show off the skills of the Web site designer, and not for the users of the information. But perhaps there may be some hope for it seems that the older a Web site is, the more likely it will be to maintain its structure in the future.

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    Navigating Sam's Laser FAQ

    Under ideal conditions, Sam's Laser FAQ would be in a single file and your access to it would be via a 100 GB/s link. In a few years, such capabilities may appear primitive but for now, one can only dream of avoiding the World Wide Wait. :) Therefore, the organization of these pages ends up being a compromise. If you have the space, installing a local copy of Sam's Laser FAQ on a reasonably fast computer would be best (though you lose out on automatic updates). See: Sam's Laser FAQ Local Installation for details. The total size (V16.50) is approximately 141 MB (about 14 MB of text, the remainder graphics).

    Sam's Laser FAQ is divided into chapters and sections. Except for the introductory material including the Table of Contents (ToC), each chapter is a separate file and has its own Sub-Table of Contents (Sub-ToC) Anything smaller than a chapter is called a section and has its own header and link from the chapter's Sub-ToC. Multiple sections may be grouped where they are related to one topic or related topics. For the most part, there are no nested text files. With one or two possible exceptions, the only files below the text files are those for diagrams and photos. To minimize download time, there are no in-line graphics anywhere except the Laser Equipment Gallery where relaxation is encouraged. :)

    Links to return to the ToC are located at the beginning of every chapter and links to return to its Sub-ToC (top of page) are located at the end of the chapter as well as between major sections. There is also a link at the end of every chapter to the next chapter.

    Hyperlinks within the text will either be to other chapters or sections of Sam's Laser FAQ (in which case they will generally be preceded with "chapter:" or "section:" as appropriate) or to other pages on this Web site or elsewhere. All local links have complete URLs including the filename so it is possible to tell if the link is to some other page (if the filename doesn't match the one currently being read).

    All of Sam's Laser FAQ uses the very simplest HTML. This is partly because I have to maintain it and partly to avoid fluff. :) I have thought about adding a framed entry point which would include the ToC(s) down the left edge and would be interested in any opinions you may have on this and other formatting issues.

    I realize that a fast search facility would be really nice. Eventually, I may have one (I refuse to use free search engines that impose advertising. They tend to be too slow anyhow.) In the meantime, realize that you can always use Ctrl-F in your browser to search any single document. The two special files: Sam's Laser FAQ Expanded ToC and Sam's Laser FAQ Comprehensive Table of Contents provide a means of using this technique to find desired topics with a minimum of effort. You can also use the search engine on the Drexel S.E.R FAQ Mirror Site. However, if someone would offer to provide a fast non-commercial search engine that I can just drop in with near zero effort, please contact me me via the Sci.Electronics.Repair FAQ Email Links Page.

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    Sam's Laser FAQ Sites

    Check out the Home and Mirror Site Locations page for a list of places to find Sam's Laser FAQ (as well as the complete Sci.Electronics.Repair (S.E.R) FAQ and Silicon Sam's Technology Resource (SSTR). There, you will also find Links to ZIP files with the latest version of the complete Sam's Laser FAQ and SSTR. Currently, the most up-to-date versions are at RepairFAQ.Org and UPenn. But for most practical purposes, even older versions are still 99.9% useful since much of the newest material is quite specific and related to the intricacies of lasers like the HP-5517FL. :)

    I have collected a few ancient snapshots of Sam's Laser FAQ for pure amusement purposes. Go to Sam's Laser FAQ Archive.

    We are always looking for contributions (of all types) in any and all laser related areas to expand the content of these sites.

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    Computer Resources for FAQ Development

    Most of the text/html content for the Sci.Electronics.Repair FAQ and Sam's Laser FAQ is developed in emacs on a unix system via telnet/ssh. While some people may consider such an arrangement archaic, this allows for rapid creation and editing, accessibility to the original files from anywhere in the Universe via an Internet connection, less need to upload or download files to my PC, and professionally managed system maintenance, upgrades, and backup. Sounds like the newest Cloud services, huh? But I've been doing it that way for decades.

    I currently have access to accounts at the University of Pennsylvania (UPenn), Drexel University (though this one is temporarily unavailable), and a third site that I keep low key for private use. These are used to create, edit, and test the material in the Sci.Electronics.Repair FAQ and Sam's Laser FAQ. The primary account I use for FAQ development is at UPenn and this seems to be secure for the moment the situation can change from one year to the next. The Drexel computer is probably reliable as far as a long term relationship but for some reason, USENET access is limited and posting doesn't seem to work at all.

    Therefore, while not critical for the near future, I am always looking for access to 1 or 2 additional unix or linux systems, preferably at academic institutions like colleges or universities, but I will also consider other types of not-for-profit organizations. For obvious reasons, I really do not want to do this in association with anything commercial. My needs are modest: 5 GB of disk space, telnet or ssh, ftp or sftp, emacs/gnus read/post, muttmail, and publicly accessible Web space. Most of what I do is editing and email so processing requirements are modest and shouldn't impact other activities. However, a reliable supported environment is critical to my sanity so your personal server farm isn't something of much interest. :)

    I do not want and will not accept monetary contributions for this effort. But, a way to help the FAQ development would be to provide stable computer access. If you know of, or are able to offer such a resource, please contact me via the Sci.Electronics.Repair FAQ Email Links Page. However, I really only am interested in something that's likely to remain stable 10 years out, not an ancient PC running in the crawl space under your back porch. :) In return, of course, you get a local copy of the absolutely latest and greatest versions of the FAQs (and space permitting), all the associated ancillary material. And, of course, priority email replies to technical questions! Thank you! :)

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    Version Update Information

    While there may be small updates as well as more substantial additions almost daily, when the number of revised and added bits reaches a critical (but random) threshold, the version number will change. Beyond a larger but also random threshold, an entry is added here to summarize the major enhancements that may be noteworthy, and the version number will increment by a large (also random) number. But, even if the version number doesn't change, the date of this page and Sam's Laser FAQ Comprehensive Table of Contents will always reflect the latest ZIP file archive. The ZIP file archive is updated whenever a file (like a .gif) is added to the Laser FAQ, or at some somewhat random interval, usually less than 1 week or month. If you aren't totally confused by now, send me email and explain what I just said so I will understand it. :) The bottom line is that just because the version of this file hasn't changed doesn't mean nothing is happening, only that I've been lazy about updating it! ;-) And even with a new version entry, there can be many many other additions not listed!

    What's New as of V19.80

    What's New as of V19.60

    What's New as of V16.50

    What's New as of V14.50

    What's New as of V13.00

    What's New as of V11.00

    What's New as of V10.00

    What's New as of V9.90

    What's New as of V9.80

    What's New as of V9.10

    What's New as of V8.75

    What's New as of V8.50

    What's New as of V8.25

    What's New as of V8.00

    What's New as of V7.75

    What's New as of V7.50

    What's New as of V7.00

    What's New as of V6.60

    What's New as of V6.40

    What's New as of V6.25

    What's New as of V6.10

    What's New as of V5.90

    What's New as of V5.60

    What's New as of V5.35

    What's New as of V5.20

    What's New as of V5.00

    What's New as of V4.75

    What's New as of V4.40

    What's New as of V4.25

    What's New as of V4.00

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