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which one is stronger: blue or red diode?

alx

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I'm still confused regarding blue and red lasers, because i saw that blue LD can achieve 120mW at 120-130mA, and red LD can achieve 250mW or more at 420mA. In this case, in my opinion first option for a buyer should be the red LD, but seems that mostly, peoples want phr-803t diodes.

1. Why? Just to change the color and obtain a weaker laser (blue laser power =0.5*red laser power)?

2. can anyone tell me which laser diode is stronger, regarding thermal output power? the blue one cropped from phr-803t or the red one cropped from lpc-815?

3. Which one is more sensitive to human skin?

Let me explain: I just build my first laser (using a red LD). first, i was scarred and afraid to not roast my skin, being very carefully when I'm manipulating it. By mistake, i crossed my laser over my hand and discovered that i can't feel something on my skin... I kept the laser shining my hand for another 15-20 seconds and still nothing. i become very disappointed, thinking that my laser is broken.... but is not! my laser can lit matches 2m away in few seconds.

4. what is the MINIMUM thermal output power for a red laser (if the laser has the ability to lit matches)?

5. In my case (lit matches 2 meters away, red LOC, current around 400mA, axz glass lens) how much could be the output power?

Regards,
Alx
 



pullbangdead

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First, it's not blue, it's violet, the "blu-ray" is just a marketing term.  The light coming out is violet.

1. It's a different color.  A lot of people like the color.  It makes things fluoresce.  And, people generally have both of them anyway.

2. You've already listed the output power.  Power is power.  The optical output is the theoretical maximum thermal power that can be put into a target, same thing.  Past the numbers you already listed, it's just about how much of the light is absorbed by whatever you're hitting.  Skin reflects most of the red light, it doesn't absorb it.  Skin absorbs violet light, though.  Try putting a black spot on your arm with a marker, and then hit that spot with the red laser.  The black color will make more of the red light get absorbed.  

3. See above.

4. The minimum power to do any task, such as light a match, is all relative.  Matches are all different, the laser can be focused differently, you can use a magnifying glass for an even smaller focal point, etc.  It's all relative, so there's no exact number.

5. A red LOC with a glass Aixiz lens at 400mW is like above 250mW IIRC, but I might be a little off.
 

691175002

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In raw power red will come out on top however violet is absorbed far more readily than red. For example, 100mW of violet can burn white paper which is something red would struggle to accomplish. Same deal with skin, red light can travel through skin without much difficulty so when you shine the red laser on your hand the light is being spread out. The blue light cannot travel through your skin and thus all the power is dumped into a very small point. Even unfocused, a PHR can be easily felt.

I don't see what the problem with liking a laser just for its color is. 0.2mW of yellow can cost hundreds of dollars. IMO The color is far more useful as most of us buy lasers primarily to look at and because they are cool. IMO Burning gets old after two or three matches, and you can only burn under controlled circumstances with protective eyewear. I'll take beautiful colors any day.
 

alx

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691175002 said:
For example, 100mW of violet can burn white paper... Same deal with skin. Even unfocused, a PHR can be easily felt.

..you can only burn under controlled circumstances with protective eyewear. I'll take beautiful colors any day.
I finished today my first blue laser too, based on phr. Indeed, you are right. I can feel on my hand from 1m away, but... i cannot burn anything!!! Is powered at 118mA, so, it should be over 100mW. I think is a focus/colimating lens problem. With my first red laser, it was possible to light matches ONLY when has been replaced the original plastic lens with AIXIZ glass lens. On blu laser, i tried:
- aixiz plastic
- aixiz glass (seems to be better collimated, blue dot is smaller)
- dx plastic lens
Now, is running with dx plastic lens which comes with original housing module. I cannot burn white paper even if is closer (less then 20cm) and cannot lit matches.

Can you tell me please, in your case, what was the distance you tried and worked to lit matches/burn white paper? What lens are you using? As i read/know, for red lasers, glass lens are recommended but for blu, only plastic lens are good to be used. In my case, no one is working.

alx
 

691175002

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I used the normal plastic aixiz lens. You absolutely need laser goggles to be able to focus it properly. There are videos where 30mW of 404nm is lighting matches.
I normally burn from a few inches away, when you are properly focused moving even a few millimeters closer or further away will make a huge difference.
 

Spyderz20x6

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pullbangdead said:
First, it's not blue, it's violet, the "blu-ray" is just a marketing term.  The light coming out is violet.

1. It's a different color.  A lot of people like the color.  It makes things fluoresce.  And, people generally have both of them anyway.

2. You've already listed the output power.  Power is power.  The optical output is the theoretical maximum thermal power that can be put into a target, same thing.  Past the numbers you already listed, it's just about how much of the light is absorbed by whatever you're hitting.  Skin reflects most of the red light, it doesn't absorb it.  Skin absorbs violet light, though.  Try putting a black spot on your arm with a marker, and then hit that spot with the red laser.  The black color will make more of the red light get absorbed.  

3. See above.

4. The minimum power to do any task, such as light a match, is all relative.  Matches are all different, the laser can be focused differently, you can use a magnifying glass for an even smaller focal point, etc.  It's all relative, so there's no exact number.

A red LOC with a glass Aixiz5.  lens at 400mA is like above 250mW IIRC, but I might be a little off.
Umm... you're kinda off... ::)
At 400mA, it should be around 200mW. at 450mA, it will be around 250mW with an AixiZ glass.
 

ndrew2505

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Spyderz20x6 said:
Umm... you're kinda off... ::)
At 400mA, it should be around 200mW. at 450mA, it will be around 250mW with an AixiZ glass.
so are you... an lpc diode will give you 200mw at 350ma and thats after an aixiz acrylic lens  ;)
 

Spyderz20x6

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drew said:
[quote author=Spyderz20x6 link=1235431288/0#5 date=1235863982]
Umm... you're kinda off... ::)
At 400mA, it should be around 200mW. at 450mA, it will be around 250mW with an AixiZ glass.
so are you... an lpc diode will give you 200mw at 350ma and thats after an aixiz acrylic lens  ;)[/quote]
I've never had one do that...
 

pullbangdead

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Only one thing will settle this: a fight to the death.

Ready, and...



GO!!!!!
 

ndrew2505

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the red liquid sky in my avatar is a lpc diode at 350ma putting out ~197mw after an acrylic lens, closer to 190mw after the lpc dichro mirror i used...
 

Spyderz20x6

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drew said:
the red liquid sky in my avatar is a lpc diode at 350ma putting out ~197mw after an acrylic lens, closer to 190mw after the lpc dichro mirror i used...
Interesting...
Well, as you know, all diodes vary...
 




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