Entering the Laser World

Hi everyone, I apologize if all my questions have been asked before, but I really did do my best to read up on the information on these forums. Trouble is, there's just so much to keep track of. The last time I checked, green lasers were exotic and couldn't be had for less than $50. Now I see that people are making their own blue lasers, so powerful that you need specially tinted glasses to use them.

Anyway, needless to say, learning about this whole new world has excited the engineer in me, and I'm particularly interested in the burning blue lasers. As I understand it (feel free to correct me, as I probably have a lot of misconceptions about lasers) the 445nm lasers are best suited and most cost effective for burning anything, even white paper, due to their high energy frequency.

I think I want to try building my own, so I can learn more about lasers. I realize that this will be difficult, but I'm up for a challenge, and I do know how to solder. Is this the most cost-effective option? I see some people posting that it would cost less to buy yobresal's lasers instead. Also, I know that a 1 watt laser isn't a toy by any means. Is there a way I could include a switch or use different batteries so one laser can be both a high powered instrument and a fun laser pointer? Finally, how much wattage would I need to burn white paper, and what's the maximum wattage I could safely use indoors without safety glasses?

Thank you

Welcome to LPF!

I myself wouldn't use a laser over say 5mW indoors without safety goggles on just in case you hit something reflective and gets you in the eye

Also have you had a look at Jayrobs kits?

I think 5mW is a tad over kill I would say be cautious under 50. 50-500 watch your ass 500+ Use your judgment. I am not advising anything and high powers are dangerous. If you have self control and are aware of your surroundings, you should be fine. I don't advise burning without goggles. ( I do it at an intense squint but don't suggest it)

I agree it could be overkill but I'd rather be safe and cover my @$$

Why do people use @$$. You can say Ass, lol. Also, I trust myself enough. If you cant trust you who can you.

Haha yeah well...

On topic I'd rather not recommend someone use a 50mW indoors without goggles.
That's what I meant by to cover my ASS.

Oh Yeah, I said I don't advise. Up there.

Thanks a lot! That kit build looks like a neat project. I looked into it and found an assembly video on youtube (from a user named styropyro); doesn't look as difficult as I thought it would be. So it looks like I need a driver for the laser, and the ones I've seen come preset. Is there such a thing as a variable output driver, or could I use two drivers (one at a watt and the other below 50mW) and select between them with a switch?

Technically the best for burning power per milliwatt is 405nm, but since for the same price as a 200mw 405nm you can build a 1.6 W blue that would probably be the best option, and yes anything above 500mw will burn white paper nicely, as you go up it gets faster and even causes flame instead of just smoldering. Building is a great way to learn about lasers, I have done it before, but I recommend you start with cheaper diodes, like say a red diode, instead of accidentally frying a $60 445 diode (I learned the hard way). Document your build too, people love to help and give - usually - constructive criticism that prevents you from throwing away money. You could have two drivers set to different ma that would make it easy to switch a handheld form say "labby mode" to "pointer mode" - not sure if this has been done - or, just an idea, use a potentiometer on the side to change it more minutely. A meter would also help for this but not sure if thats possible in a hand held. Glad to see your reading and interested!

but if you want burning at a distance you would need to go 405 anyways because of the great beam characteristics. you can ignite a match at over 40 feet.

Thanks, More Power and Chipdouglas. So a 445 nm laser will not light a match at 40 feet? It seems like for 405nm, 800mW is pretty common, and no one seems to drive 12X modules over a watt. But for 445, there are plenty of people who drive the 130/140 module to produce a watt of power or more, so I'd think that a 1.2 watt 445nm would burn better over distance than a 800mW 405nm laser. Am I wrong on that?

Also, if I were to build a 445 using the Jayrob host, it looks like the Flexdrive is my best bet. I'm not sure based on the circuit diagram whether I can add a switch in to change the power output. It looks like there are 5 contact points that must be disconnected for the lowest load, but connected for the highest? Also, I've now learned that the 130/140 has a minimum threshold, so it would not be possible to, say, make a 5mW laser with that diode. Does anyone know what the lowest current I could drive the diode at is for it to still be reliable? Also, what's the maximum current I could set without risking damage to the piece?

^^^^ correct.. you are wrong. LoL.. remember my key words in my other post... "great beam characteristics" the 445 does not have this. the 445 is a multimode diode and puts out an uglu uncontrolable beam with bad divergence. it also has a rectangular bar type beam profile where as the 405 is a nice tight dot. this is the reason you cant necessarilly overcome the distance issue. Also it is not common to push 405's to 800mw.

michael.

The lowest possible power for the diode to lase is 200ma, which gives it 7mw. The highest is debatable. 1.6A is definitely safe, an experiment was done 10 sec on 10 sec off for about 3 months 24-7 with less than 5% degrading power. The highest I would go is 1.75 A. The Frankenstein build has been running at this power for a while now with little negative effects on the diode.

I meant that you should have two flex drives, one set to say 200ma and one set to 1.5A (cant get higher then that without 2) and you could switch between the two. Could be wrong but I don't think it is possible to add a switch to the board itself.