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ArcticMyst Security by Avery

Pros/Cons of Common wavelengths

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Sep 5, 2013
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Hello all, Alex here. I remember seeing in a thread a few days back a thread on what are some of the Pros & Cons about "Common" Wavelengths.

I haven't seen any post on this so I decided to take a crack at this, hope you enjoy

405nm
Picture:100mW-405nm-Violet-Purple-Blue-Laser-Module-Focused-Dot-M405D10031670_1 | Flickr - Photo Sharing!

Pro's
- Is a stable wavelength, which means you do not have to worry about temperature affecting performance as much as 532nm
- Laser diodes are stable. 405nm as a wavelength is not "stable." Because the emission comes directly from a laser diode, the output tends to be stable despite temperature changes.
- Only wavelength which somewhat "Changes Color", if 405nm is aimed on white surfaces it turns blue.
- It's called fluorescence. If you're going to write a "guide" you NEED to know that.
- Can be used to write on Glow-in-the-dark materials
- GITD materials are "charged" by UV. Because 405nm photons are near UV, they have enough photon energy to work.

Con's
- This wavelength being at the end of the spectrum will not appear BRIGHT AT ALL
- Brightness also has dependence on power. Holding power constant, 405nm will be much less visible than wavelengths closer to the center of the visible spectrum.
- Cannot be had in huge amounts of powers, MAX 2W.
- Yes it can. It's just very expensive. That is a very important distinction.

445nm
Picture:445nm | Flickr - Photo Sharing!

Pro's:
- Can be had at incredible amounts of power for cheap
- This depends on someone's concept of "incredible." Perhaps mentioning that up to over 3W can be had for just a few hundred dollars would work better.
- Is the best wavelength for burning/lighting combustible materials
- 405nm is the best commonly available wavelength to burn with, holding power constant. This is due to the photon energy inherent to shorter wavelengths. Similarly, 355nm would "burn" better than 405nm, holding power constant. Additionally, materials don't have to be strictly "combustible" to be marked by lasers.
- Have beautiful beams
- That's kind of subjective, isn't it?

Con's:
- (Even thought not noticeable) have an ugly rectangular aperture beam

532nm
Picture:1mW-532nm-Green-Laser-Module-Single-DotM532D131660_1 | Flickr - Photo Sharing!

Pro's:
- Brightest wavelength out of them all
- Brightest wavelength than others in this guide (holding power constant), yes. But not of the whole spectrum.
- Easiest wavelength to observe a beam at
- That may not be true depending on the power. This is another "holding power constant" statement that can be misleading.
- Has a nice, clear circular dot
- That depends on the quality of the laser. Cheap Chinese pointers often have messy dots that change shape as different transverse modes come and go. By saying this, you might lead a newcomer to buy a laser that will disappoint them, because the dot does not live up to "circular."

Con's
- Can be highly unstable, temperature will easily affect power output
- If not thermally stabilized, yes.
- Can easily be damaged
- Due to the fragility of the alignment. Might want to mention that.
- Price rapidly climbs as output of unit increases $$$$
- It starts climbing earlier. Every wavelength has a power at which the price starts to skyrocket.


650nm
Picture:red-laser-module-5mw-focusable-650nm-dot-798974-Gallay | Flickr - Photo Sharing!

Pro's:
- Most readily available wavelength for purchase(can be found everywhere)
- Indeed!
- Can be had at high powers for cheap
- This depends entirely on your concept of high power. This needs clarification.
- Highly stable
- Laser diodes are stable. 650nm is not inherently stable. There are DPSS options for 650nm that invalidate this statement.

Con's:
- Worst wavelength for burning/lighting(Some materials)
- Of this list, perhaps. It is not the "worst" of all wavelengths...


Thank you for reading, this is just a quick, fast easy thread for new users who may be deciding on which wavelength is best for them.

Like always, it all depends on what you will be using you're laser for, different wavelengths will excel in different domains.

Like always, if you feel this need any re-adjustments, please do not hesitate to write a post below and I will get to it as quickly as possible
 
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Jul 12, 2013
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405nm changes dot color for any florescent material I have observed magenta blue bright greenish and a white

Also red would only be bad at burning a red object. just like it would be hard to burn a green object with 532
red diodes also have the cheapest price per mW a ML101U29-25 = 1.5 cents per mW. an lpc-826 3.4 cents per mW. m140 4.8 cents per mW.
s06j 6.1 cents per mW. 5W cmount 650nm 8 cents per mw mitsu 500mW 11 cents per mW. PL520 $1.06 per mW.
 
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I'm with black wolf. My 405's (quite the collection actually lol) change dot color constantly. Fun laser however.
 
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They are however more dangerous as they have an (extremely small) chance of causing skin cancer because they have some uv. Fun laser however.

Never. 405nm is a visible spectrum, non-ionizing radiation. So, no skin cancer. :tsk:

edit:
@Tha Greenlander
I'e read somewhere that >650nm can drain power from glow in the dark materials, instead of ionizing them. Actually, I've tested that with a 650nm laser... Inconsistent results though.

Suggestion:
Writing something about how each WL is commonly generated would be cool.
405nm, 445nm, 520nm, 635nm, 660nm, IR's > diode
473nm, 532nm, 589nm, etc > dpss

IR lasers
Pros
High powers available cheap;

Cons
Invisible to the eye, still dangerous.
High powers available cheap.
hard to aim and focus without IR sensitive camera
 
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Yeah, its UVB you need to worry about. UVB is NEVER a worry coming out of 405's

(granted, any radiation of any wavelength has a chance of causing cancer in cells... just much less likely.)

max 2W for 405nm? The highest I've heard of is 1.2W.

Also 650nm and 405nm are good for distance burning.

Edit: as for the 650nm, confirmed, but varies with different GITD materials.
 
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Also you've left out 520:

Much more stable than 532 since it's a diode
Slightly less visible than 532 therefore not as bright mW for mW
More expensive than 532
Limited power options
 
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Also you've left out 520:

Much more stable than 532 since it's a diode
Slightly less visible than 532 therefore not as bright mW for mW
More expensive than 532
Limited power options

520nm isn't a common wavelength :beer:

But in fact all that you have said is true, much more stable then 532nm and definitely more $.
 
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520 was my first build. It's just as easy to get a hold of, and about the same price of a 445. It's not as commonly used because it isn't a high power diode, not to mention it's relatively new.

Just because it isn't in an ebay pen doesn't make it uncommon. :)
 
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520 was my first build. It's just as easy to get a hold of, and about the same price of a 445. It's not as commonly used because it isn't a high power diode, not to mention it's relatively new.

Just because it isn't in an ebay pen doesn't make it uncommon. :)

Haha, I know just because it isn't a eBay pen it dosen't mean it's not uncommon.

And how did you get it at *almost* the same price as 445nm? When I cheack it's in the 100$'s for 50mW, but the diode itself may be cheaper. Not going to argue with you since you have build one and I haven't :beer:
 
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DTR has 80mW 520 diodes and driver sets for $128 Here

And 3W 9mm diode and driver sets for $117 Here

I call an $11 difference negligible but to some that my be significant...
 
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Wheres the 808nm? 808nm is very cheap in very high powers. Just rip apart a $6 eBay pen for 500mW of 808nm.

You can reclaim 808nm diodes very cheap.

And multimode rectangular beams can be very cool at times. Though a round beam is preferred the most.

Most people are going to buy lasers with visible wavelength's :) and by the way im making a Equality collection now :beer:
 
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Regarding 405nm:

- Only wavelength which somewhat "Changes Color", if 405nm is aimed on white surfaces it turns blue.

This "change of color" phenomenon is called fluorescence.
405nm is not the only wavelength that causes fluorescence in other objects.
Just about any wavelength with enough energy to excite electrons will create this effect.
Try shining your greenie on an orange hi-lighter.

When fluorescence occurs, the laser light is not changing color but is exciting the electrons in the atoms of the material that is illuminated. When they are excited, they "jump" to a higher energy level.
When the electrons relax, they return to a lower energy state and the energy they absorb is re-emitted as light. The wavelength of the light is dependent on which level the electron transitioned from and to.
Short wavelengths like 405nm and 445nm seem to be the best for fluorescence because their high-energy photons can excite the electrons in a variety of materials to emit light that is energetic enough for us to see. In other words, fluorescence may occur with other, longer wavelengths as well but the light emitted may not be in the visible spectrum, since fluorescence tends to produce light of a longer wavelength than the light that was absorbed.

This process is similar to phosphorescence (glow in the dark) and stimulated emission... which is what gives us the technology that this forum is all about!
 

Trevor

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I don't want to be an ass and go through and correct everything here, but this "guide" contains a lot of misleading, unscientific, or downright wrong information. Sacrificing exhaustiveness for simplicity is understandable, but people may walk away from this guide sort of understanding what while not at all understanding why. We don't do magic here. ;)

I appreciate your enthusiasm and your desire to contribute to the forum, but you may want to be in the hobby a bit longer before you start writing guides. This reads like "guides" that were on the Wicked Lasers forum.

I don't want to be mean, but I also don't want to see new people misled. I can post what I think should be changed, if you want?

Trevor
 

Trevor

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lol JK but yes I do see errors on this. Not all 532s are unstable, if they use a half-decent crystal it will be stable. It should be that 532 and ALL DPSS lasers are fragile. If you drop it, you can knock the alignment out.

The "quality" of the crystal is far less important than the thermal stabilization and alignment. You can make cheap, Chinese laser crystals sing and dance if you're patient and knowledgable enough.

Trevor
 




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