How to Make a Burning Laser from a Regular Laser?
Most of us will understand the concept of lasers used for laser pointers, or even those Star Wars lightsabers that we all love to play with. However, if you do not have the budget to buy a burning laser outright, how do you go about making one from a regular laser pointer?
The Fundamentals of Burning Laser
What does mW mean in lasers?
The first measurement we need to understand is the power rating “mW”. mW stands for milliwatts, a measure of energy. In lasers, mW is used as a unit to describe the power of lasers. Basically the higher the power, the brighter the dot and beam will be. Also, with more power comes more burning capability.
Early laser pointers were helium–neon (HeNe) gas lasers and generated laser radiation at 633 nanometers (nm), usually designed to produce a laser beam with an output power under 1 milliwatt (mW). The least expensive laser pointers use a deep-red laser diode near the 650 nm wavelength.
What mW laser will burn?
A standard 1mW to 5mW laser pointer is not capable of burning but a 50mW, 250mW or 1000mW laser will readily burn many materials. 10 mW is enough to melt black plastics and burst balloons, while lasers of 100mW and above can light up paper.
What color laser is best for burning? Lasers that light matches and burn paper
A 1W (1000mW) green 532nm laser and a 1W (1000mW) blue laser should light up matches and burn paper.
Are burning lasers illegal?
In the U.S., it is legal under federal law to own a laser of any power. Under federal law, it is perfectly legal to sell any laser above 5 mW as long as the laser complies with FDA/ CDRH laser product requirements for labels, safety features and quality control; and as long as the laser is not promoted as a “laser pointer” or for pointing purposes.
If a laser over 5 mW is called a “pointer” or is sold for pointing purposes, the person performing the illegal act is the manufacturer or seller. If the consumer (end user) has a mislabeled or non-compliant laser, it is legal for them to possess it. We are not aware of any cases where a non-compliant consumer laser has been taken from its owner simply for being mislabeled, or because it did not have the safety features of its class. However, we would recommend you to upgrade to a compliant version, as the FDA would likely require the seller to refund or replace the product.
What are laser mW ratings?
The mW rating measures the output of power from the laser. The power of the laser in a laser pointer is the most important measure of how the laser performs and the type of tasks for which it is suitable. Laser pointer power is measured in milliwatts, which is denoted with "mW" in laser pointer descriptions. The following chart lays out what the different power ranges on laser pointers mean for their use.
Laser pointer power chart
This chart lays out the power ranges on laser pointers according to their class level. There are some practical applications of lasers listed for comparisons, such as visibility in varying conditions, and their effect on human skin.
Class I: < 0.5mW
Class II: 0.5 - 1mW
Class IIIa: 1 - 5 mW
Class IIIb: 5-500 mW
Laser beam visible at the point of contact
Visible in smoke or fog
Visible in clear conditions
Stings skin on contact
How to make a burning laser from a regular laser?
To make a burning laser, one principle you must understand is the refraction of light through a convex lens. A lens is a transparent piece that may be made up of glass or plastic. It has at least one surface that is curved. When light rays pass through the lens, they get refracted, or change direction, due to the shape of the lens.
A convex lens is a converging lens. As you can see in the image above, the lens surface bulges out in the middle. As parallel light rays pass through it, they bend inwards and converge at a spot called the “focal point”. In modern laser pointers, laser diodes are used to produce powerful light beams, which then travel through a convex lens. These beams then converge at a focal point, producing concentrated light energy.
Step 1 – Parts.
To make a burning laser the most important part is the laser pointer. In this DIY, we use a pack of 3 color laser pointers including a red, a green, and a violet/ blue. They are all rated at 5mW. Wavelengths are 650nm, 532nm, and 405nm respectively.
The next step is how you will attach the lens to the laser pointers. An electrical tape would suffice to get it burning and is a good thing to try out if you want to decide if it’s worth making a better mount.
Step 2 – Get your lens
The other critical piece you will need is a lens that should be convex. Find a source with a relatively high-quality convex lens. It only needs to be as wide as your laser’s beam.
In this DIY, we use a set of needle nose pliers to unscrew the lens from a dead green laser pointer.
Step 3 - Attachment
With An Electrical Tape
Line up the plastic housing and tape away.
With A Delrin
Cut the lens off of the rest of the housing and drill a hole for it in the Delrin and press fit onto the silver part at the front of the laser.
Step 4 - Burn
Now that you have mounted your lens it’s time to test it by burning some stuff. Be careful while doing this - the beam is very focused and the light that bounces off could easily blind you. Try it on objects such as paper, balloons and matchsticks rather than on humans or animals.
Images courtesy of: https://www.instructables.com/id/Easiest-way-to-make-a-laser-burn/
That’s it, all you need is 4 simple steps to turn a regular laser into a burning laser!
We hope you’ve benefited from this short guide about making burning lasers from regular lasers safely. Remember, if in doubt, always consult an expert or your local hardware store – you do not want to get hurt while playing with lasers!