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FrozenGate by Avery

Long distance burning - Question

L

Leoprix

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Sep 2, 2011
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Hi all,
I'm going to build my first 1,5/2 W 445 nm diode laser using a 1w diode and FlexDrive V5. I would like to understand if it will be possible to install lenses to reach burning capability up to 60/80 feet. What is the best lens assembly to adjust focus up to that long distance?
Thanks for help!
Leonardo
 
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no... the diode is multimode and has bad diveregence. if you must burn at that distance a 12x blu ray is pretty much your only option in a hand held. or you can get a really high powered green dpss lab style.

michael.
 
Yea... what Chip said:

With a 12x diode (405nm) you can achieve the best results in burning at dinstance compared to the price.
Of course a 1W Green with a beam expander x10 will do better but price is a lot higher.
Im able to burn with my 405 Laser at about 5 meters away. It has got very good divergence that means I could pop a ballon even at 10 meters away (didn't try it yet ^^)
 
What's the output of the 12x blueray and what kind of voltage/current do you put through it for that? Trying to decide what laser I'd like to build next.
 
Noy sure on the voltage. Up to 6vdc but the correct driver batterry combo covers that. As to current... 550 is dangerous max for diode. And 500ma is the norm
 
DeathOfAllThings said:
What's the output of the 12x blueray and what kind of voltage/current do you put through it for that? Trying to decide what laser I'd like to build next.
Click to expand...


The V5 Flex will take care of the voltage for you. Typically it is ~6V.
 
Thanks for suggest. So I need a 12x instead of the Casio A140 diode. The V5 flex could be the driver, but what about the best lens to focus the beam at 20/30 meters away?
Leonardo
 
As best alternative, you suggest a green DPSS Lab laser. I found some on ebay. But I have no experience to evaluate all tech characteristics to evaluate how much it will be suitable for long distance burning (Divergence? Exit beam dimension? Adjustable lens? Output power?). For example:
A 300 mW like this:
300mw 532nm DPSS Green Lab Laser Module With TTL | eBay
Or this 500 mW (but for light show): 500mw 532nm DPSS Green laser Diode/Module for lightshow | eBay
Or this (more expensive) 400 mW: 400mw+ 532nm Green DPSS Laser Output Over 550mw! TTL | eBay

Or others?
Thanks for help!
Leonardo
 
you can calculate the "burning power" at a fixed distance by the following formula:

BP=power/(π(beam diameter-beam divergence*distance)^2)/2
 
Thanks Arayan,
but "n" ...what is?
I can suppose that the "burning power" will depend also on how much the beam is focused. So I suppose that the "divergence" (calulated from the source) will depend on the focusing lens system setting. If the beam is focused near the laser, I think I will have big divergence, but if I can adjust the focus to have a very small dot at 60 feet, I will have small divergence. May be I am wrong. Sorry, but I have not too much experience. Thanks.
 
I'm sorry it isn't "n" but Pi... it's very difficult to write using an iPod :p

... yes the focus is important but the formula is for a beam of a coherent light without optics. To obtain a best divergence you can use a beam expander.
 
this thread caught my attention especially the reply from Burnsy.
may i ask what is he highest power 405nm in the market now?

thanks a million
 
A 1watt 405 is not the norm. About 700mw is. And thats a burning monster. Especially since blurays have such good beam quality.

At leo.... Please delete the name of the company you posted. The are a pain in the ass and give the admin hell.
 
Bigger lens will lower the divergence. 1W 445nm has bad beam shape, that's true. But if you can make it burn at 2m with 5mm lens, you will achieve generally the same dot at 20m with 50mm lens. Actually during my experiments with large aperture lens it seemed that the beam profile is better with bigger lens.
Because of angle at which the beam leaves the diode can, photographic lens can be used pretty effectively. You need lens as simple as possible, because every air/glass transition will eat some power. So generally no zoom lens.
I tried simple 50mm (focal length), and also 500mm (about 90mm diameter) mirror long range lens, both worked rather well. Except I did not use it with my high power laser, only at about 200mW, and the alignment was pretty bad, so it did no burn at all. But the dot looked rather good. I still plan to hook it to my 1.5W ..
Btw. you better use something you don't intend using on camera anymore .. the laser can damage it. And I'm not just talking about plastic cases, which are so popular these days in photographic lens design. Laser can for example vaporize some grease inside the lens, which would be pretty hard to clean.
 
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Yes, DrSid.
This is exactly what I mean. If I can have very good burning beam for a 2W 445 nm laser at 1 m distance, I can reach more or less the same dot (so the same burning energy) also at 20 or 30 m distance, obviously with a suitable lens. Could you tell me when you will have test your 1,5 W with a standard 50 mm relfex lens? I have two old glass 50 mm lens for relfex and I am courios to know.
Thanks.
Leonardo
 
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