So...can someone tell me why we don't have a usuable P60 laser dropin by now? I mean, if a cheapo laser can clear 5 miles, but is not useful for illumination, can't we up the power and distill the beam to be held in a Solarforce host or something? If not, why not? I want 2,000 meters of throw in my pocket. Why hasn't this emerged???
High power lasers are expensive. They can’t tolerate high heat like leds can. Most people want useful white flashlights with halfway decent color rendition. A good white requires a mixture of colors. Each laser can only produce a single color with a very narrow spectral bandwidth (wavelength spread). You can create some kind of white from RGB or even blue and yellow lasers. Phosphors in white leds or RGB displays can create a better spread of wavelengths giving a better white. Combining laser beams requires precision alignment and beams of the same divergence (spread). Cheap chinese + precision does not go together well.
I know due to our current supply chain—we assume “cheap Chinese”
but the OP asked about “useable” , presumably even if made in
small custom-ish production runs.
Don’t know anything about Lasers—Are you saying the cost is prohibitive for all but
hand made units?
A high power white laser will be costly even in production runs. Since yellow lasers are expensive and low power, it would currently require RGB. So precision alignment of 3 lasers and dichroic filters to combine the beams. High precision to keep the beams together over a long distance.
But there is a bigger problem. A laser is only bright because it’s in a tight beam. Spread it out to any useful size spot and it’s no longer that bright. You’re going to need a lot power.
Why are you assuming white?
Color wasn’t mentioned—just the desire for a modular solution.
Check it out.
http://www.audi.com/com/brand/en/vorsprung_durch_technik/content/2014/04/laser-high-beam.html
Single color is not very useful for illumination. But If anyone wants to try out single color laser as a “flashlight” then just get a very high power adjustable focus green or red laser. I wouldn’t recommend single color blue as it can be hazardous to your eyes even unfocused.
All of the “laser” car headlights just use the laser to illuminate a phosphor. The white light from the phosphor then needs to be focused with reflectors and /or lenses, much like an led.
OK. Good. Now this is starting to make a little sense.
Not to mention the fact that in the US, Australia, and many other countries lasers over 5mW are prohibited (illegal) So the throw you’re wanting can at the very minimum get your laser quickly confiscated and at the maximum land you with big fines or in jail.
Oh, I know they are illegal, and I hate them for the dangers they are, but I am talking about using the hardcore focusing and transferring it into a light engine whereby it can be diffused and somehow modified into a super thrower with the help of a special lens and reflector. It just seems like it should be easy to do.
Someone mentioned building a multi led red flashlight with 3 or 4 different shades of red leds. Reason being that the narrow spectral bandwidth (wavelength spread) of any one colored led limits its usefulness for illumination. If you you increase the range of spectrum by adding slightly different reds then it becomes much more useful. And thats just with leds. Lasers have an even narrower spectral bandwidth then leds.
Dang your hide Joe! Now you got me thinking about how to do that!
Last I knew (haven’t followed laser news closely for awhile) in the USA it’s illegal to sell a handheld laser (laser pointer) over 5mW. It is not illegal to own or use lasers with powers over 5mW. Also not illegal to sell laser diodes, drivers or components.
~ edit ~ to add “handheld”
Correct.
Of course your local cop may believe it must be illegal (or know it’s legal but still tell you your a criminal).
The police here say the laws are circumspect to interpretation by the individual officer and would likely be turned over to state authority, which in turn would probably make it a federal offense. While it might not be illegal to buy the diodes in an unassembled form, assembling them immediately makes it bounce over the lines. All depends of course upon how it’s used in the end and if any complaints are filed or if an officer spots the use and investigates. One flash on an airplane and they’re looking for you, even if it’s inadvertent. Buttheads have fixed that up.
Luckily individual officers don’t get to interpret laws. No matter what a few officers might like to think. Unfortunately for too many it’s just “assume it’s illegal and arrest ’em”. This is 2015 why can’t an officer type into his car computer “laser” and get back basic info. Possession: legal. Aiming at people, animals, vehicles, PLANES: illegal.
It would need to meet requirements to be a federal offense. Aka cop says you aimed at a plane. 
Pray that flight plans show there was not a single plane near you at the time.
How powerful of a laser do you need once diffused to make an useful beam? Anybody nerd enough to figure that out?
“Useful Beam” isn’t exactly a scientificly quantifiable amount.
Useful for what? Under what parameters?
Lasers to lumens: Luminosity of lasers (math) | Candle Power Flashlight Forum
I would call a 10 ft diameter spot to be around the minimum useful size. I’d really want 20 ft or more. But of course other opinions will differ.