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445nm vs 405nm

Wallyl

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I have a 1000mw 445 blue laser and look to be ordering a 500mw 405 violet laser. As I understand it the violet is much dimmer because it has 1/2 the output and the human eye is far less responsive to violet light. I ask anyone that has both if they wouldn't mind describing the difference. I am not into burning lasers; I just like how they look shining into the sky on a dark night.
 





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as you say a 405 beam is very dim even a powerful like 500mW will be noway as bright as a blue or green but it should be visible in a dark room. To me its perhaps the best looking color and i would say anyone that has a 445 should def get a 405.

U can see my lame avatar pic attempt, thats my 100mW 405 laser it turned out a little brigher on the camera then it really is but it should give u an idea perhaps..
 
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Wallyl

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Thank you mortuus. I have three 301 Lasers in Red, Green, & Blue---they Red & Green are very bright...but the Violet is extremely dim. However the laser beam can be seen in a dark sky. But it has a terrible divergence. But the Violet is a beautiful color; so I will have to get one. My 1000mw 445 Blue is a Leserbtb HL. I see that you have their HL's in Blue, Violet, & Green...but no Red?
 
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Yes those 301 lasers are usually not that great but they are good for people to buy since they are cheap and you can get an overspec laser usually, no red thats correct i dont plan to buy one either for now.
 

Wallyl

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I have purchased 4 and all work well...I gave a Green to a good buddy and he loves it. He thought about upgrading and quickly determined that it would cost a bundle more to get one that is only slightly brighter.

I guess you don't like red because the beam is much too dim.. I have a 301 Red and Green. On a dark night in the country on a large farm I compared the two. At one mile I could see both dots on trees. The red was easier to see because it had less divergence and the green laser beam was so bright that it made it difficult to "pick-up" the green dot at that distance. I am thinking of getting a HL660-300 to go with the HL445-1000.
 
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...but the Violet is extremely dim... But it has a terrible divergence.

My 16x blue ray 405nm has terrible divergence too, but it is a single mode laser diode which should have better divergence, I thought. I don't understand why the beam spread is worse, why?
 
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Divergence is a function of beam quality and size. So if the divergence of the raw diode output is small, and then you collimate with a short focal length lens, the resulting beam will be narrow and can still have high divergence despite being of high quality. Beam expanders hurt quality, but result in lower divergence precisely because they output a wider beam.
 
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You might be confusing our eye's difficulty to focus on 405nm with bad divergence. No matter how tight the beam you'll always see a 405nm dot far away "blurred" as if it was much bigger than it is.

To verify this get a good pair of laser goggles with high visible light transmission and point the laser at a fluorescent surface far away. If the dot is still spread out then you have bad divergence.
 

USAbro

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So that's why we can't focus. I remember my brother got a 405 pen and I could never focus on the dot. Amazing. I wonder how the lens in our eye reacts to this wavelength to cause the effect.
 
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Dunno, but the type of lens used makes allot of difference..

I recieved a 3.8mm >900mW 405nm laser with Edmunds FL lens.
It gives a tighter beam then a regular G-lens.

o5Zbp98.jpg
 
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To tell you truth for some reason I can clearly see the difference between a 405nm and a 445nm laser. 405nm yes it is dimmer yet you can still see the beam at night, at least i can see the difference with my Chinese 405nm comparing it to my custom made 581mw 445nm.
 
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I have a 1000mw 445 blue laser and look to be ordering a 500mw 405 violet laser. As I understand it the violet is much dimmer because it has 1/2 the output and the human eye is far less responsive to violet light. I ask anyone that has both if they wouldn't mind describing the difference. I am not into burning lasers; I just like how they look shining into the sky on a dark night.

WRONG
you are comparing apples and oranges


first 1000 mW (of 445) is NOT TWICE as 'bright' as 500mW of 445. to be twice as bright by eye you need 2000mW- and for twice that you will need 8W..
but forget all that when you try to compare 405 with 445--

IF the air is 'clean'-- no dust.. fog ..mist..smoke etc you wont see the beam of a 500 mW 405 very well --especailly from the side -- we ALWAYS see any visible leaser 'better' from the rear or from the front-- BUT expect a quicker burner from 500 mW of 405 that 1W of 445 blue.


another factor that makes 405 so dangerous is that our eyes do not see it as being 'bright' so the opening (Pup il) does not get smaller when we view 405 and that means more light can enter your eye and taht is not good -- IF thE laserBEAM happens to go directly thru the center of the eye- our own eye's lens can muLtiply the power by 100,000 times ( SOME SAY 200,000)-- SO MUCH FOR 5 mW BEING 'EYE SAFE'-- even worse- if the laser hits your fovea- worst place for a laser burn by far-- very likley that you would lose ALL vision in that eye.. also both blue(ish) and green lasers pose another danger to skin.

" Blue light hazard--- some wavelengths can cause damaging changes to tissue due to a type of photochemical reaction within the skin itself more so than other longer wavelengths are capable of. This reaction is very different from thermal tissue burns and may occur with long term exposure of significantly lower power levels than longer wavelengths require to cause similar damage." 1

1 (ILDA LSO study guide/manual)
 
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405 vs 450.
405 is a spoiled wavelength. The light of 405nm interacts with almost everything and shines in blueish (florescence). By itself it is really dim to the human eye.

Be careful!
 




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