Tips for making your own own DIY laser depend on the components you start with and how powerful you want the laser to be. A common approach to making a fairly powerful DIY laser is to take a digital video disk (DVD) drive that burns DVDs using a red wavelength laser, and use the laser diode component inside it in to construct a new handheld laser built into a mini flashlight. Building a DIY laser of this level can be fun and educational, but the final product is also dangerous and should not be considered a toy under any circumstances.
Unplug the DVD drive from any computer or power source and begin to disassemble it. The only part you want to keep is the actual laser diode assembly, which looks like a small, clear glass, light-emitting diode (LED) bulb mounted in a metal component casing. Next, determine the polarity of the laser diode prongs by running power to them from two 1.5 volt AA batteries connected in series, with the positive end of one battery connected to the negative end of the other, creating a 3-volt battery. The laser will light up when you have matched the positive battery end to the positive diode connection, and the negative battery end to the negative diode connection. The third step is to buy an inexpensive AIXIZ laser diode housing in the 650-nanometer, 3.2-volt range available online, remove the enclosed diode, and plug your DVD diode into it in the original one’s place. Finally, take a 3-volt mini flashlight, remove the standard bulb assembly, and replace it with your laser diode, soldering the positive lead to the positive connection in the flashlight and the negative lead to the negative connection in the flashlight.
A DIY laser of this type is quite powerful, and should never be pointed at any person or animal’s eyes or body, even momentarily, at cars or aircraft and so on. It is strong enough to pop balloons, light candles, and start campfires, but should not be treated carelessly or given to children. More powerful CO2 or chemical laser plans are also available freely online, but they require a high-voltage supply, vacuum pumps, compressed gasses, cooling systems, and a sophisticated understanding of optics and electronics. Regardless of the level of DIY laser that you build, keep in mind that its use may be strictly limited by local laws and it may legally be classified as a weapon, so it should only be operated in carefully controlled conditions under adult supervision.