650/808nm PBS cube Idea

[zxn474l]

I have a 650nm laser that is 200mw cw and is housed in a mini brass housing with adjustable focus set to infinity for burning and pointing and had an idea of joining it in a PBS cube to let the red 650nm through continously and set a 2 watt 9mm 808nm diode housed in an Aixiz module with a glass lens set to a short focal point of say 2 feet and have a circuit breaker on off switch for it to activate it when I want to and leave it off the rest of the time. What I have in mind is making a "tricked out" laser host that can put out a bright thin beam in fog for effects and then switch on the 808nm through the cube bringing the burning power up to 2200mw of raw burning power to cut and burn things but keeping the 808nm a secret hidden. Will the 808nm cast any HAZE on the 650nm beam in fog working like this? What about without fog? The red will be set to infinity and the 808nm set close range only and has a high nm range. Inputs or advice would be helpful. Each will have a seperate power supply but a "double pole" swich allowing both lasers to work through one momentay switch when the 808nm is switched on by the button.

 

[billg519]

Well, to even try this, you'll need a Meredith module for 9mm. The aixiz module is for a 5.6mm diode, and if you drill the aixiz out to fit a 9mm, there is very little left to transfer heat to a heatsink. Also, you may need a focal point closer than 24" with an aixiz type lens. You may not get a good burning point past 8 to 10". Reason is the two axis diverge at different rates, so the spot rapidly becomes rectangular. You could use a cylinder lens and an aspheric.

Remember that anyone observing the operation of this trick laser will need goggles. 2W of IR is not a trivial amount.

 

[Things]

PBS cubes are designed to split/join only a single wavelengths, you can't combine 650 and 808nm with a PBS cube, you would need some form of specialized dichro.

 

[maxh]

PBS cubes are designed to split/join only a single wavelengths, you can't combine 650 and 808nm with a PBS cube, you would need some form of specialized dichro.

Well either the cubes in some of the blu-ray sleds are not PBS cubes, or PBS cubes designed for one wavelength still work decently for other wavelengths. One of the cubes in the KES-400 sled can combine red and violet just fine, and seems to work on the principle of polarization. As you rotate the red and violet modules, the beam of each will go from mostly transmitted to mostly reflected and vice versa. Any idea what may be happening there?

 

[Krutz]

PBS are used to join/split differently polarized beams. this has nothing to do with wavelength. you may combine two lasers with different wavelengths as well as with the same wavelength.

i dont expect that 2w of 808nm would be too visible, and probably not noticeable.. thats just guesses!

about two watts and safety: two watts are absolutely dangerous! its no rocket science though. if its focused, it will spread after the focal point. once it spreads out enough, it would eventually reach class I powerdensity. calculate it, with a worst-case of 1cm² pupil-area and staring into the beam. if its not much more than one mw per cm², i call it safe. even when invisible (which makes it more dangerous).
sure, if someone holds his eye closer to the laser, its quickly much more than that..
so far for shining the beam around (which will happen eventually).
second problem is "operating" the laser. 2w focused down to a burning pinpoint is a lot of energy! if you hold it at arms length, the uniform reflection may be too much already, play with the numbers!
the real problem is, however, that the reflection is not uniform. you point to random objects, some of them may surprisingly be totally reflective to 808nm (did you guess coke and permanent-markers are nearly transparent in IR? see?). and, even worse: while burning, the surface melts. liquid surfaces reflect really well! ever used some visible laser to melt an opaque, frosted surface? like chocolate, for example? noticed that suddenly, bright and almost focused reflections were flying all around? imagine 2 watts, where you dont realize it! ..could be staring into half a watt for a second, for this! which is absolutely enough to terminate your eyesight unrecoverable..

i thought about similar ideas, burning and doing tricks with combined high-power IR and visible "pilot lasers". that IR laser is collecting dust, i never built it, and never will.

thats everyones own decision. as long as you give out googles to the people who cant decide, because they dont know!!

but then.. shine around with the weak red, handle out googles. make it a show, make it funny, people will laugh their ass off about googles and a weak red pointer. then push the button.. harr harr!
thinking about it, that might be a cool effect, not? ;-)

manuel