So, you want to build a laser? You’ve come to the right place. There is a vast amount of knowledge here that will get you on your feet. However, there are several things you must know about lasers in order to operate them, and operate them safely. All of this material will be covered here in this tutorial.

What is a laser? LASER is actually an acronym that stands for “Light Amplification by Stimulated Emission of Radiation”. Unlike regular light that we see in our everyday lives, laser light is monochromatic, meaning that the light it contains is that of a single wavelength. The wavelengths of lasers we typically deal with here are measured in Nanometers (nm), and typically fall into the Visible Spectrum. The Visible Spectrum falls into the 400nm ~ 700nm range and consists of the colors Violet, Blue, Green, Yellow, Orange and Red. Violet is on the shorter (more energetic) side of the spectrum around 400nm, and Red is on the larger (less energetic) side of the spectrum around 700nm. Any light with a wavelength shorter than 400nm falls into the Ultraviolet (UV) range. This light is invisible. However do remember that just because you can’t see it, that doesn’t mean it’s not there. After UV you have X-Rays and Gamma Rays; however we’re not going to touch up on either of those two wavelengths because chances are you’ll never even see such a laser emitting in those wavelengths. Any light with a wavelength larger than 700nm is considered Infrared (IR) light. IR is also invisible to the human eye; however some people can slightly make out IR light up to about 800nm. Again do remember that just because you can’t see it that doesn’t mean it’s not there. After IR you have Microwaves and Radio waves. Like X-Rays and Gamma Rays, we’re not going to talk about Microwaves and Radio waves because chances are you’ll never encounter a laser emitting in such wavelengths. You can refer to the picture below for an illustration (Thanks goes to Scotty 757 for providing us with this image & Louis E. Keiner from Coastal Carolina University for providing this data).


Different lasers have different output powers. Output powers are typically measured in milli Watts (mW). However, lasers with outputs of Watts (W) and even Kilo Watts (KW) do exist. There are several different groups that laser output belongs to.

Class I: Inherently safe; no possibility of eye damage. This can be either because of a low output power (in which case eye damage is impossible even after hours of exposure), or due to an enclosure preventing user access to the laser beam during normal operation, such as in CD players or laser printers.

Class II: The blink reflex of the human eye (aversion response) will prevent eye damage, unless the person deliberately stares into the beam for an extended period. Output power may be up to 1 mW. This class includes only lasers that emit visible light. Some laser pointers are in this category.

Class IIa: A region in the low-power end of Class II, where the laser requires in excess of 1000 seconds of continuous viewing to produce a burn to the retina. Supermarket laser scanners are in this subclass.

Class IIIa: Lasers in this class are mostly dangerous in combination with optical instruments which change the beam diameter or power density. Output power does not exceed 5 mW. Beam power density may not exceed 2.5 mW/square cm. Many laser sights for firearms and laser pointers are in this category.

Class IIIb: Lasers in this class may cause damage if the beam enters the eye directly. This generally applies to lasers powered from 5–500 mW. Lasers in this category can cause permanent eye damage with exposures of 1/100th of a second or less depending on the strength of the laser. A diffuse reflection is generally not hazardous but specular reflections can be just as dangerous as direct exposures. Protective eyewear is recommended when direct beam viewing of Class IIIb lasers may occur. Lasers at the high power end of this class may also present a fire hazard and can lightly burn skin.

Class IV: Lasers in this class have output powers of more than 500 mW in the beam and may cause severe, permanent damage to eye or skin without being magnified by optics of eye or instrumentation. Diffuse reflections of the laser beam can be hazardous to skin or eye within the Nominal Hazard Zone. Many industrial, scientific, military, and medical lasers are in this category.

Besides output power, there are several other things you need to know about the output of your laser. They are as follows.

Operating Mode: This tells you if your laser is operating in a Continuous Wave of Pulsed Wave.

Beam Divergence: As we all know, light expands as it travels. Beam Divergence is how much the beam expands over a given distance and is measured in milliradians (mRad).

Beam Diameter: This is the measurement of the beam’s diameter at the aperture of the lens.

Transverse Mode: This is the mode in which the laser operates, and this affects the shape of the beam. Please refer to the chart below for reference.


There are a few different types of lasers that exist today. The most common ones are Diode Lasers. A Diode Laser is a fragile semiconductor that must be handled with great care. For more information regarding the architecture of these devices, you can click here. Diode lasers typically operate at 405nm, 660nm, and 808nm. There are other wavelengths out there; however these are the common ones that you’ll most likely encounter.

Next on the list, you have Diode Pumped Solid State (DPSS) lasers. These lasers typically consist of an 808nm diode along with special crystals. These crystals alter the wavelength of the 808nm diode into colors not normally achieved with diodes such as green (532nm), blue (473nm) and yellow (589nm). These crystals must be placed in precise positions in order for them to function correctly. This is due to the polarization of the light. As you should know, light travels in waves. From your orientation, these waves can be traveling up and down, or from side to side. The way they are traveling is referred to its polarization. You can read more details on that here.

The next type of laser you may encounter are called Gas Lasers. Gas lasers consist of an enclosed tube with a low pressure gas or combination of gasses inside of it. This gas in this tube is then excited by high voltage. The type of gas or gasses determines the wavelength. A few examples of gas lasers are Carbon Dioxide (CO2) which lase in the far IR region, Helium-Neon (HeNe) which lase in the Visible Spectrum and Argon-Ion lasers which also lase in the Visible Spectrum.

Well, those are the basics about lasers. Now, let’s talk about how to construct a diode laser. As mentioned before, there are several types of laser diodes that lase in several different wavelengths including 405nm (Blu-Ray Laser), 660nm (DVD-R Laser) and 808nm laser. In order to construct a laser, you’re going to need the following.

Diode: As mentioned, this is what emits the laser light. A diode typically has three pins, and must be wired accordingly in order to operate correctly. Please click here for a vast list of diodes and their pin configurations (Thanks goes to nikokapo for arranging all of this data into one neat thread for all of us). That list also provides you with typical power consumptions of diodes. If the diode is not wired correctly, damage and or death to the diode will result. Please note the image provided.


Driver: This is also known as a current regulator. Laser Diodes are very sensitive electronic components, and require only a certain amount of current to operate. This current is typically measured in milliamps (mA). A milliamp is one-thousandth of an ampere of current. Drivers have different power ratings which you must pay attention to in order to avoid damage to both the driver and the diode. Most drivers will have an adjustable potentiometer in order to change the output current of the driver to your liking. In order to determine how much power you should drive your Blu-Ray diode with; please refer to the chart below (This chart is provided thanks to LarryDFW). Please note that this chart is for reference only and, and is not a guarantee. By using this chart, you acknowledge that no one will be held accountable for your diode if it should happen to die.


This data is updated often, please check here for updates.

Power: All electronic components obviously require power. This can come from either a battery or a plug in power source.

Module: The module is what houses the laser diode, and the collaminating lens. The collaminating lens takes the light emitted from the diode and arranges it into a tight, coherent laser beam. We typically use the Aixiz module around here, which contains by default an acrylic lens. There are other various collaminating lenses out there however; each designed for specific wavelengths of light. These special lenses have an AR coating on them which allows more light to pass through opposed to the acrylic lens, thus resulting in more output power. We typically use the Aixiz module because it supports 5.6mm diodes, which is the typical size of the diodes we typically handle.

Heatsink: This component is optional, however it is highly recommended if you value your diode. As anyone with basic electronics knowledge knows, electricity generates heat due to friction. Therefore, this heat must be dissipated from your laser diode due to their sensitive nature. Using a heatsink will keep your diode cooler, and will allow you to run your diode for longer periods of time (Duty Cycle).

Host: This component is also optional, however most people use a host for their lasers. A host is basically a case that houses all of the above components for easy operation, such as a pen style host. Below is an example of a typical pen host.


So, now you have all of your components. Now what do you do? Well, you’re going to need to solder them of course. You’re going to need a soldering iron, and some solder to achieve this. If you don’t know what a soldering iron is, then go read up on them and come back. Here’s what you need to do to get your diode to work.

1) Set the current for your driver. Your diode will need a certain amount of power in order to operate. Please refer to the Diode Compilation List in order to determine the proper current for your diode. Once you have that current, you’ll need to set the current on your driver. You’re also going to need a test load for this. A Laser Diode operates at a certain voltage. What the test load does is simulate the voltage of the driver so that this way you can more accurately set the current of your driver. Please refer to the image below which clearly explains what you need to do in order to set the current. This diagram is courtesy of LPF member Rog8811.


2) Once you have set your driver, you will then need to connect your driver to your laser diode. Note that you driver will have four solder points. For now, we’ll be working with the positive and negative output. Please refer to your driver’s manual in order to determine which point is which. Once you have established these points, you’re ready to solder. When soldering the laser diode, I recommend you pre-tin the pins. This will make them easier to solder to your driver (or if you’re soldering the pin to wires which connect to the driver). As mentioned, the laser diode is very sensitive, and this includes heat. If you hold your soldering iron on the diode pin for more than a second or two, consider it dead. If you pre-tin your diode pins, you’ll be able to solder it by simply placing a tiny drop of solder on the tip of the head, and then touching the iron to the pin for a split second. Once this is done, wire the rest of the driver accordingly. Do bear in mind that no matter how many volts you feed your driver with, the output current will remain the same.

3) The rest more or less depends on your host, and is a simple matter of completing an electrical circuit.
Now that your laser is complete, fire it up and see if it works. If it does, congratulations on your first build. Notice how bright the dot is? Well, the inside of the beam is even brighter, brighter than the sun in fact. If that beam were to enter your eye, you’d instantly receive retinal burns, which is permanent damage to the retina of your eye. This would leave a permanent dark spot in your field of vision for the rest of your life. Obviously safety precautions must be taken to safe guard your vision. For this, you’re going to need Laser Safety Glasses. Basically, these are glasses specifically designed to block out a specific wavelength of light. These glasses come with different levels of protection which is measured in Optical Density (OD). The higher the OD rating, the more the glasses will block out that specific wavelength. Each whole OD rating reduces the lasers brightness by a factor of 10. So, if you have a 200mW laser and OD 2 Laser Safety Glasses, your dot will appear to be about 2mW bright. Laser safety glasses can put a dent in your wallet, but you have to ask yourself this question. “Are my eyes & my vision worth trying to save a few dollars?”. If you answered yes to that question, then perhaps the laser hobby isn’t for you. If you answered no, then save up a few dollars and buy yourself some protection. You’ll thank yourself if you ever catch a reflection to the eye.

Well, that’s about it. If you have any questions, you can contact me here. All I ask is you don’t ask me any questions that were already covered in this tutorial.

http://laserpointerforums.com/members/mfo/

You’re going to need to register for an account there before you can send me PM. If you decide to send me a PM, please be aware that it will be posted in the F.A.Q. section directly under this, so make sure you spell check because I won't be editing anything. Thanks for reading my tutorial and enjoy your new laser.

Also, here's a downloadable PDF version of this tutorial to keep on your computer when you're not online.

http://laserpointerforums.com/attach...1&d=1265313699

Still not 100% sure of what you're doing? Here are some F.A.Q.

I'm not going to provide the information as to where to obtain drivers in order to keep this tutorial from being biased. There are several types of drivers out there, each with it's own pro's and con's. You'll just have to see what's available and which best suits your needs.

Green light is appears the brightest to us because as you said, our eyes are most sensitive to it. Green light is in the middle of the visible of the spectrum, thus making it the most sensitive to our eyes. Please refer to the chart below.

Not bad, However (just trying to help get this right)

Coherent = the waves are lined up perfectly
monochromatic = all the same wavelength.

I can and will delete this if it upsets you, I'm going back to read more.

Noo, I welcome this dude. Multiple heads are better than one. I'm typing this in a word document, and this edit will be reflected in the next update either later or tomorrow depending on how lazy I am :P

+1
I see this becoming a very useful thread... Looking forward to more info

It's coming. I should post an update later and fix the links. Also once this is finalized, I will also upload a downloadable pdf so that users can download all of this information and keep it while they are offline.

Although it's fine for what we do, "Beam Divergence: As we all know, light expands as it travels. Beam Divergence is how much the beam expands over a given distance and is measured in miliRad"

milliRad is just short for milliradians.

Just to expand on this a little more:

coherent: waves that have a constant phase difference, so this means that no matter which point on two waves you are they always have the same difference.

monochromatic: same wavelength or frequency.

This guide is great, and I can see you have put loads of effort into and we all apreciate it, all though most of the information in their until recently I didn't understand, so unless you have a minimum of age 16 physics it's going to be quite difficult to understand, but it doesn't harm people reading it and getting an idea

Cheers for the effort mfo, it might be an idea for someone to put together a condensed laser builing guide so that people can build one without much of the background info, I would be willing to put one together if it sounds like a good idea =]

Thanks for clearing that up.........

@ mfo, very well thought out & well constructed sentences that make this easy to read & digest with very little trouble, even for the newbies. NICE JOB !!! rob

Two thumbs up from me so far! I see you've put some real work into this. Kudos!

Thanks guys. Now we just need to find a way to lead newbies here so that they actually read all of this. I will most likely post an update tomorrow. Anything you think I should touch up on?

This is exactly what I have been looking for. I am 14 and a newbie and because you worded everything so simple, I got it! Most other threads explaining something use smart talk and it seems like it was made for experienced people in the subject of lasers. This is made for newbies. I just wanted to know what goes in a laser, what it does, and where it goes and you pretty much summed it up. If I could rep you a million times I would take the time to do it.

Sorry for the double post but I have a Electromagnetic Spectrum picture that emphasises more on the visable wavelength.

Looking good man...

I will link it when I play people greeter.

This has been updated. I guess I am more or less done with this, unless anyone else has something I should add. If so, let me know.

You really expect me to use a chart that has tampons, depends, mail order x-ray glasses and things of that nature?...

Thanks for the feedback though...

Good work MFO!!

if anyone cares to see the offensive post in question, send me a PM and I will show it to you

Meh, I just thought people wanted to know the wavelength of the main death star laser, but it's your guide.

The wavelength of the main death star laser?....

Do me a favor and stop flooding my guide with this rubbish please.

Alright, sorry.

Gosh, I was all over the net the last couple of days, looking for this very information you have right HERE! It was here all this time, really I went right past it and started reading threads the first day, got lost and continued my search on the net. Just tonight, looking over the board here and there, I found it! I have been a newbie on other forums over the years of different topics and I confess, I never ever, I mean never read "Newcomers > Rules" ever! (to my disadvantage I am sure) I am glad I finally did tonight, Hope this helps to get the word out. Great Forum By The WAY!

Glad I could help. If you want to thank me, spread the word.

I added it to my notepad greeting.......

I will gladly spread the word. I put it in my signature.