There are two lasers inside a DVD burner and one of them is a high power red diode laser. According to Internet research, the diode produces 220 mW of power. Using the information Kip Kay made available on the Instructables website, I removed the high power diode from a DVD burner and mounted it inside a plastic project box. There are two switches mounted inside the box. The first is a toggle switch to arm the laser. The second is a momentary push button switch to fire it. The completed project is smaller than 3" by 5" and weighs less than 3 ounces with its two "AAA" batteries.
I measured the current in the circuit at 260 mA and the battery voltage at 2.8 volts. Therefore the power consumed by the circuit is 730 mW. With a laser output of 220 mW, the laser diode's efficiency is 30% and its waste heat is 510 mW.