Originally Posted By: KenK
I'd love to know the difference in distance visibility between a upper-end LED light (like a Fenix or Surefire single CR123 version) in flashing mode and a Greatland Rescue Laser Flare.

No flashlight will come close to a laser. There are two problems:

1. At 532nm green DPSS lasers are essentially at the frequency to which the human eye is most is most sensitive, and all of the output power is (hopefully!) at that best-case frequency to be seen by a rescuer. A flash light spreads its power over a wide range frequencies with not much at any particular frequency and wastes much power on frequencies the human eye isn't very sensitive to.

2. The beam of a laser is usually very tightly focused and diverges slowly with distance. Even a mile away the beam is tight enough that the power illuminates a small area. By contrast a flashlight beam expands rapidly, even with a "tight focus" reflector: the beam is much larger at 50 feet than at 10 feet.

The total output power of a flashlight might be an impressively large number but that power is spread over a very large area after a short distance, and the total energy is spread out over many colors so that no one frequency (color) is bright. A 35w handheld HID might be a match for a 1mW greenie at some ranges but I'd except lasers to win in almost every other case.