Laser pointers between 5 mW and 499 mW are considered Class 3B. This type of laser pointer is very dangerous, even if anyone accidentally exposes anyone to the beam, it is illegal and will be arrested and imprisoned. Although it is no longer illegal to own or use such lasers, if you expose others to the beam, even accidentally, it is a criminal offence. Class 3B laser pointers can ignite paper, melt plastic, burn wood, and even the diffuse reflection of walls or paper can cause eye damage. The law usually requires laser goggles of this power laser and above. The legality of these lasers is a bit of a gray area. You can buy this type of laser pointer from China.
Usually the Laser pointer stops at about 10 watt hours. It becomes very difficult to provide them with batteries and they can overheat because more power is dissipated in the device than contained in the beam. Laser manufacturers sometimes claim an efficiency of 30% or higher, but in reality, an efficiency of 10% is typical. How to achieve it? Use a magnifying glass. All you need to do is point the magnifying glass at an object, such as a black plastic bag or a match. Flash through the glass with an ordinary laser. When the plastic starts to smoke or the match lights up, you will look at it in surprise. Refocus the lens. When you refocus the lens, you are actually letting the lens direct all the laser pointer light to a focal point. It becomes a burning laser because all the power, such as 5mW, is concentrated in one area.