What are Laser Pointers?

Michael Anissimov
Michael Anissimov

The laser pointer was originally invented as a handy tool for lecturers or speakers to focus attention on particular part of a screen or chalkboard.  Since the early 1990s, however, they have become extremely cheap, and are now bought primarily for the sake of being a novelty electronics item. Most use a 630 nm wavelength red laser diode, and typically output about 5 mW (milliwatts) of power, making them Class IIIa laser devices, which means that they are safe for consumer use.

A small laser pointer on a carabiner.
A small laser pointer on a carabiner.

Green laser pointers have a 532 nm wavelength, and are about 50 times stronger than red ones.  They are viewable in mid-air, whereas red lasers generally are not, with a very long range of as far as 1.5 miles (about 2.5 km) in heavy darkness.  Green lasers are more expensive than red ones, however.  Even shorter-wavelength blue lasers are also in development.

A laser pointer resembles a pen.
A laser pointer resembles a pen.

Laser pointers are typically about 0.04 inch (1 mm) wide at their source.  Some produce light at a wavelength higher than the visible spectrum, which is then filtered through a frequency doubler to produce visible light.

The light produced by a laser point is within the visible light range of the electromagnetic spectrum.
The light produced by a laser point is within the visible light range of the electromagnetic spectrum.

Laser pointers are used as cat toys, sights for firearms, tools for optics experiments, to play with, and for presentations.  They have frequently been used to pull pranks, some of them dangerous. When shined in the eyes, they can temporarily impair vision, cause the person to see spots, and in rare cases, even damage the retina. Some people have shined them into the eyes of airplane pilots, truck drivers, musicians, and others appearing onstage, causing problems with their vision.  For this reason, health agencies have issued strong warnings against the use of laser pointers for mischievous purposes, and these devices are often forbidden from concert halls and sporting events.  It is illegal to shine a laser pointer at a police officer, for example.

Inexpensive pointers, in conjunction with a few other devices, have been successfully used by hobbyists to produce high-quality holograms.  They have also been used to blind security cameras.  Some nations have worked on superpowered laser pointers as antipersonnel weapons, but a U.N. resolution adopted in 1996 forbids their use in warfare.  These lasers, not always above the blinding threshold, are often referred to as "dazzlers."

Laser pointers can be a useful tool for professors teaching in a large lecture hall.
Laser pointers can be a useful tool for professors teaching in a large lecture hall.
Michael Anissimov
Michael Anissimov

Michael is a longtime EasyTechJunkie contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments


My boss uses a yellow laser pointer. It is so bright that it looks like an intense ray of sunlight!

I know that it was expensive, because he won't let anyone else use it. He keeps it locked away in a box, too.


Green laser pointers really are powerful. My friend had one, and he showed me just how far it could reach one night.

We went outside and he pointed it to a spot way down the road. I could actually see the green dot that far away!

We had to turn it off once a vehicle approached, though. We didn't want to blind anyone and cause an accident.


@cloudel – Cats and dogs supposedly can't see red things, but they can still detect light very well. So, they are just seeing a bright dot of light on the floor or wall that is moving, and they want to chase it.

My dog barks at it after trying for awhile to capture it. When I can see that he's getting frustrated, I hold the light in one spot and toss a dog biscuit right on top of it. Then, I turn off the laser pointer.


I thought that cats were colorblind. How can they see the red dot of a laser pointer? Does the fact that they can see it mean that maybe scientists were wrong about them being colorblind?


@LoriCharlie - People definitely do play pranks with laser pointers. I know that every concert venue I've been to over the last couple of years has had signs banning laser pointers. A lot of those places also search purses and things on the way in to make sure people aren't bringing in stuff they shouldn't, including laser pointers.


I never knew laser pointers had so many uses. When I was in college I had a few professors that would use laser pointers, and of course I knew that they were used on guns. However, I did not know they made great cat toys or that so many people used them to pull pranks.

I guess laser pointer pranks must be pretty popular though, if organizations have gotten enough complaints they had to write warnings about them.


@starrynight - Laser pointers do make great cat toys, but I read somewhere you have to be careful, because it can be psychologically damaging to the cat. They can get really frustrated, because they can never actually "catch" the laser pointer no matter how much they chase it.

I've heard a good solution to this is to give the cat a treat when you get done playing with the laser pointer so the cat feels like he's accomplished something.


@ddljohn - My cat goes nuts over the laser pointer too! I was really happy when I realized I could get my cat to chase around colored laser pointers, because my cat is really skittish. I have a hard time getting him interested in a lot of toys, because he's scared of things that make too much noise.

So the laser pointer is perfect for him. It moves around and gets him interested, but he doesn't get scared of it because it doesn't make any noise. So it's a win for everyone, because I find his antics chasing the laser pointer very entertaining.


What's the difference between yellow, blue and green beam laser pointers?


I think laser pointers are really dangerous. I read an article the other which talked about how there are hundreds of plane accidents every year because someone blinds the pilot with a laser pointer while he's landing.

It's definitely not a smart thing to do and I'm sure the people who are doing this are probably kids playing around just to see what happens. But they are putting people's lives in danger. If the pilot can't see, he can't land the plane, it's as simple as that.

Anyway, the Federal Aviation Administration has apparently taken a stand against this and announced a huge monetary fee for anyone who's caught aiming a laser pointer at a plane. Good for them!


My cat loves playing with laser pointer pens. Whenever she becomes lazy and refuses to play with her mouse, I use the laser pointer to grab her attention.

First she looks at it to see what's happening and then will start following it with her eyes and will pounce on the laser to try to catch it. It's so cute!

I'm sure the person who invented laser pointers didn't think that it could be used as a cat toy but it's a favorite with most cats.

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