LASER vs. LED: What’s the Difference? 4.88/5 (139)

I’ve always been fascinated by light.

When I was a kid, my first flashlight fascination soon developed into wiring electronic circuits and messing with LEDs. When I set out, at age 10, to build a robot, the first item I included was the lights. By the time high school came around, I was studying laser physics and wishing I could afford an actual Laser. I still remember the day I got to play with my first laser–it was an obsolete helium-neon beast that had been donated to our school. By today’s standards, it was quite primitive. But it would put a dot on a building 200 yards away and I was hooked.

Well, times have certainly changed. Lasers are now common, affordable, and widely available–but they’re still not very widely understood. And they’re often confused with LEDs. So here’s a quick, non-boring primer about lasers, LEDs and light.

Let’s start with some cool acronyms so we can get an idea of what we’re taking about.

LED stands for Light-emitting Diode. And it’s pretty much just that. A diode that emits light when electricity passes through it. Often in pretty colors.

LASER stands for Light Amplification by Stimulation of Emitted Radiation. This mouthful of gibberish pretty much means that a source of light is amplified within a gain medium and emitted in a specific way. Cool stuff happens in the process, which we’ll discuss in short order. But first, we’ve got to tackle the concept of color.

Take a look at the sun. OK, maybe don’t look directly at it, but consider it for a moment.

Light dispersion illustration.

Sunlight appears to be white, but it’s actually made up of every color of light, including colors our eyes can’t see. That’s why sunlight can be separated into its constituent colors by a prism, or in the case of a rainbow, airborne water vapor. Included in sunlight is infrared light, which we cannot see, but we feel it as heat. Also included is invisible ultraviolet light, which is responsible for sunburns, faded upholstery, and germ-free drinking water. The point is there are many colors or wavelengths of light in sunlight.

Lasers, on the other hand, are monochromatic. This means that all the light produced by a laser is a single, specific wavelength. LEDs also tend to produce monochromatic, or nearly monochromatic light. In acupuncture, we select the color to use based on the effect we are hoping to achieve. The red colors tend to be tonifying, while blue colors tend to sedate.

So wavelength=color, and color=effect. Got it so far?

Are you coherent?

teamworkOK, our next step in this journey of discovery is the concept of coherence. To explain this one, I’m going to have to pull out a boating metaphor. Have you ever watched a rowing competition? You know, the sleek shells, the muscular guys, all rowing in perfect unison as they race along the water, while the coxswain calls out commands. One of the keys to winning is for all the rowers to work precisely together as one. This is a good metaphor for coherence.

Almost all forms of light are INcoherent. This means that each of the individual light waves pretty much does what it wants and ignores all the other light waves. Think of a rowing crew of drunken amateurs, some rowing one way, some rowing another, one playing the guitar, and one falling out of the boat. Get the picture? Though the boat may move, it won’t move powerfully or in a predictable direction.

Coherent light, on the other hand, features all the individual light waves precisely lined up with each other and working in perfect unison. They’re all going the same direction, and taking each “stroke” in the same way and at the same time. In other words, all the waves are “in phase.” Here’s an illustration:

Screen Shot 2014-02-11 at 12.13.08 AM

Though the same amount of light is coming out of both light sources, the coherent light is much more concentrated and powerful because of its coherence.

It also stays in a single beam, rather than spreading out. That’s why a laser pointer will project a very small dot across a long distance. And that’s also why laser light is dangerous for our eyes. In nature, there is no such thing as coherent light; all coherent light is artificially made. Therefore, our eyes are not adapted to deal with the intense power of coherent light deposited in a small area on the retina, and, depending on the laser power, retinal burns can result. Hence the recommendation for safety glasses.

True Lasers?

OK, this brings me to one of the most common questions I get.

“Is this a ‘true laser’ or just a diode?”

Yep, not a week goes by that I don’t get asked that. And it’s a bit of a complicated question because of laser history. You see, in the early days, lasers consisted of large tubes, external light sources, fancy mirrors, and other tricks to get the light monochromatic and coherent. The first laser I ever touched was the size of a briefcase. But now, thanks to modern technology, laser light is produced by–wait for it–diodes. In fact, nearly ALL modern lasers are diode lasers. Therefore, the question about “true lasers” versus diodes is meaningless.

But wait, doesn’t the “D” in “LED” also stand for for Diode?


And that’s where the confusion results. Diodes are the light source in LEDs AND in Lasers. So naturally, people confuse the two. But now YOU won’t because you know the difference in the light produced by each. All modern lasers are diodes. And yes, they are TRUE lasers, producing monochromatic, coherent light. Some folks hear the word, “diode” and immediately assume LED, not laser. Hence the confusion.

So When Would I Use Each?

OK, this brings us to the title of this post. Lasers vs. LEDs. When should you use a laser and when should you use an L.E.D.? It really depends on the target of your treatment and what you’re trying to accomplish.

Lasers concentrate all their power in a small point, which makes them ideal for laser acupuncture. And laser light is coherent, which also makes it ideal for this application. Lasers are used in fiber optic communication systems because coherent light can be transmitted over much greater distances than incoherent light. The coherent laser light can be transmitted hundreds, even thousands of miles through fiber optic cables without much loss. In the same way, laser light tends to penetrate easily to the meridians and travel along them, for energy-moving effects in the meridians, even at a distance from the point being treated.

So…if the meridians are fiber optic in nature (and there’s evidence they are) then coherent light is your best bet to penetrate, communicate, and move Chi.

Plus, it’s fast, painless, and effective! I get excited just thinking about it


LED’s, on the other hand, tend to distribute their power over a larger area, but without the traveling effect of laser. Therefore L.E.D. effects tend to remain local, affecting the local tissues that
are exposed to the light. Because they’re not coherent, they can safely use higher power without danger to eyes. Powerful L.E.D.’s in healing wavelengths are comfortable, safe, and produce very nice effects. In summary, LED’s are great for treating larger areas, and affecting local tissues.



Yep, I’m still fascinated with light.

Green Bar

Now, a word about safety:

Though Class IIIa lasers are generally considered “eye-safe,” this does NOT mean the lasers cannot damage the eye; rather, it means that you will most likely blink or look away before any real damage can be done.

However, out of an abundance of caution, many of our customers do choose to use laser safety glasses for their patients and themselves, just as an added layer of safetystacks_image_72

We always want to promote and encourage the safest practices possible, and so if you are going to use laser safety glasses, you need to make sure they block the wavelengths that match your lasers. They are very specific, and if you have the wrong glasses, they will not work. Usually, you’ll need separate glasses for red and blue lasers because each set of glasses will only block one wavelength. This isn’t particularly convenient when you’re using two laser colors. Fortunately, I’ve designed a single set of glasses that blocks both blue and red wavelengths in the same lens. Click on the image for more information

I hope you’ve enjoyed learning a bit more about lasers vs. LEDs.

Please rate this

Dr. Adrian Larsen

Adrian P. Larsen, D.C., F.A.S.A., C.Ac. Dr. Larsen is President of Miridia Technology Inc., and one of the developers of the AcuGraph Digital Meridian Imaging system. He currently divides his time between research, product development, and teaching. Dr. Larsen also holds certifications in Applied Kinesiology and CPK, and has specialized training in SOT and craniopathy. He, his wife, and 7 children reside in Meridian, Idaho.

33 Replies to “LASER vs. LED: What’s the Difference?

  1. I wonder if infrared light has the same wavelength as moxa?
    It would be great to have a light with moxa frequency…

  2. Nice article, educative and fun to read, thanks!

    The question that brought me here however, was a comparison between LASER and a collimated LED beam (using lenses, curved mirrors etc.). I would like to know whether it is possible to collimate an LED beam to have the same beam divergence and range as a LASER (does the LASER beam possess any form of divergence at all?). What would be the main differences between the two similar beams then?


      1. Thanks for your quick reply Sir. Can you please give the reason why it is not possible (preferably by Mathematics or Physics proof)?. A link to a website explaining this would also do :-).

  3. Hello Dr. Adrian
    If allowed I want to ask
    Can I replace the diode laser instead led
    Is it permissible together with the reasons
    Thank you

    1. Hi Dana, I’m not sure what you mean by your question. If you are asking whether you can interchange laser and LED in acupuncture use, for instance, I gave specific uses for each in the article. If that’s not your question, can you give me more detail about what you are asking?

      Thank you!

  4. Can a LED diodes of 880 penetrate into shoulder capsule? I have a 2nd L. total shoulder revision that’s needs help as well as a R. shoulder that has only replacement options for help with the constant pain/ache.

    1. The wavelength isn’t the issue so much as the power. 880 nm wavelength means you are referring to an infrared light, which generally has good penetration. If the LED has adequate power, I would expect good results for your shoulder.

  5. Hi Dr Larsen. I have neuropaty in my feet. I am not diabetic. Wath is better for my, infrared light or LED laser?

  6. You recommend Infrared light for plantar neuropathy. Would this be LED infrared light or an infrared lamp light. I have searched the internet without finding if there is a difference.

    1. An LED infrared light would be the approach I recommend. We sell a veterinary version called the Photizo Vetcare. There are other versions of high-intensity LED-based infrared lights available as well.

  7. Dear sir,

    to begin with; Thank you for writing this article.

    I help my family, friends and strangers free of charge with acupressure. (With very good results) I hope to achieve better results with the use of lasers.

    I am having problems with the purchase amount. $ 300 for 2 laser pens in a box is a lot of money for me. After much deliberation, I decide to make a purchase. (Even though I can not afford it.) But then I am confronted with shipping costs of up to $ 50! So it costs me $ 350 for 2 pens!

    Are they gilded? I work hard for other people, please help me out here.

    1. Hello! Thank you for your message and hard work. Wonderful to hear you are helping with acupressure! What a great service you are offering free of charge! It is unfortunate about the international shipping costs. We understand and please know we do not benefit from shipping prices, as the amount is autogenerated when your address is entered. Well wishes to you and many thanks!

  8. Thank you very educational. I bought a cold laser with 12 diodes 5mw 650 nm and 1 diode 60-150 mw 808nm.
    When I shine it to the wall, they look look like a diffused light..I thought laser beams are running parallel and they are focused.
    I looked again at the seller’s info and this what he says:
    The LEDs of our products are composed of 13 laser heads. They are not cheap LEDs. You can identify them by the following three aspects:
    1. In the state where the product is not illuminated, you can observe the laser emitting head with the naked eye, and you will find a golden copper cap in the middle of each emission

    It’s confusing to me. What’s your take on it?

    thank you

        1. Aim the laser at a wall 1 foot away. If there are 12 diodes, you should see 12 dots on the wall. If you only see a large, diffuse, red light projected on the wall, you don’t have lasers.

          1. Thank you for that knowledge of how to tell LED lights from actual lasers. There seem to be many fradulant people out there selling medical devices and claiming they have actual lasers. I did check my device, which is supposed to cause hair to regrow, and aimed it at the wall, a foot away, and the light was diffused. And when I looked inside when it was off, I saw that each diode had a golden copper thing on top of each. They advertised that it had 80 laser diodes at 650-675 nm wavelength. Not sure i
            f it will work on hair follicles or if I should send it back?

    1. I recently purchased a device that specified on the box and information on Amazon,that it had 80 laser diodes. I decided to see if they were “exaggerating” . I looked inside and each diode does have what looks like a golden copper head. But when put to the test of aiming it at the wall, a foot away, the light is definately diffused. Not sure what to do now. Wavelength is 650-675nm….IF they are telling the truth.

      1. If it said the word, “laser” it should make the dots on the wall. The golden copper head has nothing to do with it. If it doesn’t make the dots, it is likely not actual laser, but just LED.

So, what do you think about it?