How to Start a Fire with a Laser Pointer?

If you think laser pointers are only good for office presentations and conferences, think again! 

With the advancement of laser technology, laser pointers are becoming more and more powerful. Some even have output powers that can pop balloons, cut electrical tape, and start fires. 

That last bit often surprises people because it’s not a feature that you’d expect from a small handheld device. 

Below we’ll discuss the ways on how to start a fire with a laser pointer. We’ll also talk about the power levels and types of laser pointers that have enough power to get the job done. 

So, without waiting, let’s dive right into it! 

Can you use a laser pointer to start a fire?

The first question you’ll have to ask yourself is whether a laser pointer can start a fire. And the answer is, it depends. 

Laser pointers come in a variety of output powers and light colors. Some lasers can meet the burning beam threshold, while others might fall significantly short. 

You can’t expect to start a fire with a small pocket laser with an output of 1mW. You’ll need a laser pointer of a much higher class than that. 

So,

How strong does a laser have to be to start a fire?

The higher the output power, the stronger the beam, and the stronger the beam, the more likely it is to start a fire. The least amount of output power you’ll need to start a flame is around 500mW to 1000mW, but that would still require you to use flammable materials to assist the flame, e.g., gasoline, matches, paper, and others. 

Lasers with an output power of 3W, however, can start a fire in just a couple of seconds without the aid of flammable gasoline or matches. 

Does color play a role in starting fires with laser pointers?

Although it doesn’t matter what color laser beam you’re using, it does help make the process of starting a fire much quicker. 

Green and blue lasers have higher wavelengths, which help them achieve their color and strength. This also means they require more energy to maintain a steady light stream than a red-beam laser. 

When focused, the energy from green and blue lasers can be used to start fires.

How to start a fire with a laser pointer

First things first, you’ll have to decide what material you want to set fire to. This will help you determine how strong a laser you’ll need to make a proper flame. 

For easily combustible materials, like a match, a piece of paper, wood chips, and gasoline, a Class 3B laser should be enough to start a fire. 

Consider using a more powerful laser for more astute materials, like a Class 4 laser, which typically has an output power of 500mW.

Steps to follow

For this example, we’ll be using wood chips as our burning material. The steps to follow are similar as with other materials. However, it may change for less combustible items. 

Step 1: Find a safe space to do your experiment. 

You don’t want to end up burning your home to a crisp because of your curiosity. Before starting your experiment, find someplace where you can effectively isolate your fire so you don’t end up accidentally burning anything else. 

If you have a fire pit in your backyard, that would be a great place to conduct your trials. Otherwise, you can make your own, just like the one in this video: 

Step 2: Gather your burning materials.

Collect leftover pieces of firewood from your home and lay them out in your fire pit. You can choose to leave out combustible materials — like matches and gasoline — but if you want to speed up the process of burning, it’s completely fine to use them. 

Step 3: Put on safety equipment/gear. 

Laser pointers can cause eye damage and should be handled with care at all times. To avoid getting injured, safety goggles are recommended. Furthermore, avoid flashing your laser at other people’s eyes, directly or indirectly. 

Step 4: Setting your laser.

For lasers to start a flame, there needs to be less divergence in their beams. Divergence is essentially how far your laser increases in radius or diameter. To get a beam strong enough to start a fire, you need to set your laser to the lowest possible divergence setting. This will give you the thinnest beam. 

IMPORTANT: Most lasers use a fixed focus, meaning you can’t adjust the beam diameter/radius. However, if you can get your hands on a laser pointer with an adjustable focus setting, that would be optimum. This ensures that your beam is strong enough to ignite a flame.

Step 5: Aiming your laser. 

Point your laser at your match head (if you’re using a match) or at any clear/clean portion of your firewood — somewhere a flame can quickly build up. Flames should start to appear after 10 seconds of continuous exposure. 

The bottom line

Gone are the days when laser pointers were merely tools used in office and school meetings. Nowadays, you can do lots of cool things with them, from popping a balloon, cutting tape, igniting matches, and even starting campfires. 

It’s all a matter of output power strength and beam divergence. 

To start a flame, you need to make sure that your laser pointer has at least an output power of 500mW to 1W. Furthermore, try to get a laser pointer that has beam adjustment options so you can decrease the divergence level of your laser. 

Lastly, when experimenting with your lasers, make sure to wear safety goggles to avoid causing injury to your eyes.