Lumen ratings take into account the peak sensitivity of the human eye, so the same mw (objective output) of light nearer to 555nm (monochromatic green) will be rated higher lumens. Due to this, 683 lm per watt is the maximum possible efficiency at 555nm, but an ‘ideal’ 5800k white light source has a theoretical maximum of only 251 lm/w.
Oh I think I see. Having read this wiki page, I think that because we’re broadening the radiant flux value of the light by diffusing it’s wavelength to achieve a whiter light, the overall luminous efficacy of the light decreases, despite the luminous flux of the source remaining constant. I guess that the phosphor they use will determine how well the whole thing works out. I do think that it may still make for a better thrower though, since the originating footprint is so tiny, the surface brightness must be pretty nice.
I remember this topic from CPF a while back
Few years later now and still no laser flashlights other than the few years old wicked lasers Phosphorce
My understanding of the Wicked Lasers one is it is pretty simple. The lens assembly contains a diffraction grating (chunk of white material to diffuse the blue beam). On top of that is a layer of phosphor that emits red and green light when struck by blue light (just like on a white LED). This sits at the base of a standard flashlight reflector.
I think laser diodes are supposedly more efficient than LEDs, so in theory this could yield longer runtimes.
I can see major safety and regulatory concerns however. Also, this is a lot more expensive than spending a few $ for a cheap LED.
Laser sources (such as Osram Laser Phaser) are starting to make their way into entertainment lighting for spotlight and moving head lighting.
Blue LEDs are quite efficient so there is no advantage from that respect with a blue laser diode.
The advantage of the laser pump for the phosphor is surface brightness which gives you more throw. Unfortunately, you have to keep the phosphor cool so there is a limit currently, but its almost as high as short-arc bulbs.