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Review: 2W 405 by thanhtung

RA_pierce

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When I saw the thread, I had to have it. I took a look at the diode characterisitics and thought, "finally, a multimode diode with a respectable divergence angle."
Yes, that's right. A multimode violet laser capable of close to two Watts out the barrel and low (relatively) divergence.
Now, the diode is not rated for 2W - it's actually rated for... where did I put that datasheet?

... 5 minutes of mubling and fumbling...
Here it is!

It's rated for up to 500 mW. That's nothing to scoff at.
But look at those divergence numbers... 13 x 30 degrees typical at full angle.
The ratio is quite a bit better than the multimode diodes we're used to.
Yet there is another 0.5 W diode in existence with even better characteristics. I'd like to get my hands on one of those.

What else do you need to know?
Oh, right. There's more to a laser than output power.
We will cover the basics:
1. Build quality
B. Beam characteristics
3. Coolness

I'll go ahead and spoil the ending: the answer to all three is "yes." Please read on.

Part 1: Build quality

The laser is built in a pretty standard fashion. Machined heatsink, flashlight host, laser module.

The host is a stainless steel copy of the typical 18650-accepting variety. It looks nice but does have a logo engraved onto it. It's subtle but I do prefer unmarked hosts. The clicky switch is much better quality than on other similar lights I've seen. This design uses a solid plunger instead of an exposed spring. It feels robust like it will last a long time.


The heatsink is brass. I like brass. It's got a good natural color and doesn't turn a dingy brown as quickly as copper.
The laser module protrudes about 2mm from the front of the heatsink. I'd prefer it flush but it doesn't really bother me that much. The set screw is so tiny that none of my hex keys can fit inside. So I don't know if there's enough room for adjustment.
The surface finish on the heatsink is good but the bevel where the front of the heatsink makes contact with the lip at the front end of the flashlight is a little rough. It's only noticeable when the heatsink is removed. The surfaces that really matter look nice.
The contents of the heatsink are concealed by a round contact pad. It's set firmly and gives the whole module a nice finished look.



Here it is with one of my custom stickers. Isn't it pretty?


Overall, the build quality is good. There are a couple little things I can nitpick at, like the protruding module and the rough surface finish on the bevel but these are minor issues and don't detract from the functionality - mere cosmetics.

How about the guts?
The driver, based on what I've seen, looks good. It's thanhtung's own design and I haven't noticed any quirks during operation so it checks out. I'm not qualified to really analyze the design and I don't want to tear the module down just yet, so I will leave it at "it's good!"
The diode seems to hold up pretty well to torture. When I first fired it up, I measured above 1800 mW but while taking photos for this review, I could only get it up to 1500. This laser likes to be cold. The power will slowly drop off as it heats up. This is typical behavior for a laser with these design parameters (passive cooling, high overdrive) so I don't consider that a flaw.
I should note that my power meter may need calibration, so I will: my power meter may need calibration.
The module produces a lot of heat in a little time. I don't run the laser continuously for more than a few short bursts at a time because 1) it melts everything and 2) it gets hot. It can handle at least 30 seconds without becoming uncomfortable to hold.




Part B: Beam characteristics (pending updates!)

The promising specifications are what sold me on this laser. I bought it more for the interesting diode than anything else.

With a short focal length aspheric lens, the divergence is much lower than you'd get with any of the ~450 nm multimode diodes and way, way, way lower than the 638 nm multimode diodes.
How low, exactly?
Well, you'll have to wait for the long distance divergence measurement and comparison for the answer to that (coming soon).

Here's the beam at about 100 meters:


And a photo of my collection. The subject of this review is the rightmost laser, obviously.


Part 3: Coolness

We are all attracted to this hobby because of the coolness of lasers. We like working with our hands, we like being able to say, "look at this cool thing I made!" to people that couldn't care less, and we like thinking about ways to make the cool thing even cooler. Right?

So what makes this laser cool?
Well, it's unbearably intense. That's pretty cool. It's violet and makes stuff fluoresce. That's really cool. The latter fact is so cool it makes me want to go out and make stuff fluoresce.
This is where my hobbies and profession converge. I'm also a wildlife photographer and a biologist so, naturally, I went out to find scorpions. I found some.

I de-focused the laser (what a grammatical abomination) and blasted the ground in one of my favorite local hiking spots where I know there are many, many scorpions (at least two species are very common).
The light is so intense that it's overwhelming even when spread over a large area, so I could only really use it with UV-blocking eyewear. This works well enough for detecting scorpions. Unfortunately, scorpions are very good at detecting vibrations so even though the intense laser light didn't seem to bother them much, I had a hard time getting close enough to photograph them.
The photos below show what I was able to get. They're not impressive photos but do show that it's possible to capture the fluorescence if you get it right. The second photo was taken with my protective eyewear in front of the camera lens.
This wavelength is much too visible to be a good tool for this kind of thing. Ideally, a shorter wavelength would be used so that only the fluorescence is visible. I use a 365nm LED flashlight for this sort of thing. I'll include a couple examples of my UV fluorescence photographic experiments at the end.





Summary:

I like it. This diode is, at this time, quite unique. I'd prefer the power at around 1W. It would be less scary and it would run cooler. I prefer being conservative with output power since I don't want to blind myself or others and I don't like to worry about overheating.
However, this is not my build - it is thanhtung's, who clearly has different ideas about what a laser should be. It's a nice addition to my collection and is currently the most powerful.

Below are a couple low-resolution copies of my experiments in fluorescence photography.
These were made with a 365nm LED with a VIS filter.


 



paul1598419

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I saw that you bought this laser. It is a pretty nice multi mode 405nm diode. I might have made it a bit larger to handle the heat better and to add more or larger battery(ies). But, the review is quite well done and I very much enjoyed reading your opinions and seeing your photos. Really nice touch adding the scorpions as they do fluoresce. Thanks. :D
 

Pelagius

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RA_Pierce! I LOVE your review-for a "host" of reasons. Firstly, a very fine Laser review, including some humor "We are all attracted to this hobby because of the coolness of lasers...we like being able to say, "look at this cool thing I made!" to people that couldn't care less, and we like thinking about ways to make the cool thing even cooler. Right?"
Secondly-I too love taking nature photos-here's mine of a scorpion from the Bay Area-I had no idea solpugids fluoresce! This is with a 395nm "Black Light Flashlight". It was under one of my plant pots-getting fat on earwigs-put it back to keep up the good work1
IMG_6738.JPGesced-now I need to find one.
 

RA_pierce

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RA_Pierce! I LOVE your review-for a "host" of reasons. Firstly, a very fine Laser review, including some humor "We are all attracted to this hobby because of the coolness of lasers...we like being able to say, "look at this cool thing I made!" to people that couldn't care less, and we like thinking about ways to make the cool thing even cooler. Right?"
Secondly-I too love taking nature photos-here's mine of a scorpion from the Bay Area-I had no idea solpugids fluoresce! This is with a 395nm "Black Light Flashlight". It was under one of my plant pots-getting fat on earwigs-put it back to keep up the good work1
View attachment 61564esced-now I need to find one.
Nice!
It looks like that scorpion might be a gravid female. I haven't seen one like that that wasn't full of eggs.
Or it might be fat. That is one fat scorpion.
It looks like the image might have broken the text, though. I wonder what you meant to say.

Yeah, I was surprised to see the solifugid fluoresce blue. Apparently many spiders fluoresce as well but most of them fluoresce in the blue and UV part of the spectrum, which is really odd.
 

Pelagius

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HAha! I think it was fat. Not long before I had swarms of earwigs under my plant pots. Then I had FAT scorpions. Five plant pots- 5 scorpions. All FAT. No earwigs!
I brought a few into work (I'm a scientist in biotech) to light up with my black light flashlight. I had a range of responses-from EWWWWW to-I'm going to get my own near UV flashlight and go looking myself! One of my friends was camping in the Sierra and found scorpions outside his tent. I kept hearing "oh, I thought they were only in the desert!" I'm sure there are more-but they are easy to find all over California-as are Solpugids.
Where did you find a 365 nm flashlight? I'm wondering if I'd see more out in nature with that excitation wavelength rather than 395 nm?


Nice!
It looks like that scorpion might be a gravid female. I haven't seen one like that that wasn't full of eggs.
Or it might be fat. That is one fat scorpion.
It looks like the image might have broken the text, though. I wonder what you meant to say.

Yeah, I was surprised to see the solifugid fluoresce blue. Apparently many spiders fluoresce as well but most of them fluoresce in the blue and UV part of the spectrum, which is really odd.
 

steve001

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Nice!
It looks like that scorpion might be a gravid female. I haven't seen one like that that wasn't full of eggs.
Or it might be fat. That is one fat scorpion.
It looks like the image might have broken the text, though. I wonder what you meant to say.

Yeah, I was surprised to see the solifugid fluoresce blue. Apparently many spiders fluoresce as well but most of them fluoresce in the blue and UV part of the spectrum, which is really odd.
Look for minerals that are photoluminescent.
 

Lifetime17

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Hi,
Thats a great build of 405nm. WL, Lookslike a C6 host in SS. Yes I agree with Paul about the sinking could use a CU sink to keep that diode comfortable . But never the less an overall nice build. Enjoy awesome pics of those Scopions .. very unusual ..

Rich:)
 

BowtieGuy

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Nice write-up and photos, RA! (y)
That looks like a fun diode to have, 1W + of 405, and not have to worry too much about it dying every time you turn it on.

PS, you're going to have to stop burning the tops off of those trees! ;)
 

lasersbee

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Nice detailed reviewand info of your Laser...
Liked the Scorpion pics.
Where did you pickup the Diode ??

PM sent on LPM....;)

Jerry
 

Shotgundrums

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Very very nice!! Really nice build. Not to divert but....I was playing with Violatile tonight and her diode went splat😭 she had a good long run. It was out of a BDR-208BK. Pretty much the same as 209 Japanese version. I’m sad.😥
But, it happens. The new forum doesn’t reveal our old signatures. I had an obituary going lol.
Pierce, that’s a really nice build, I love it and it goes great with your rainbow continuation.
Cheers
SGD🍻
 

Pelagius

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RA_Pierce- I imagine the beam is visible when the lights are low-not just in the dark with 2W!

Now I want a 2W 405 nm! I like making them light up too. I'm ordering a 365 nm UV flash as my 395 lights up everything. I like the lack of backround violet in RA_Pierce's sporpion, solpugid, and Fungal shots.

Very nice. :)
Also liked the scorpion pics. I used to own emperors and did like fluorescing them as well. Nice review. (y)
 

hakzaw1

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Very nice. :)
Also liked the scorpion pics. I used to own emperors and did like fluorescing them as well. Nice review. (y)

They are by far my most fav.. and the biggest and fairly calm
not a nasty bite.. I took a blacklight bulb to work (Jerry's Pets)
and switched. with/bulb in th scorp tanks.. . sales of emperors took off.. IIRC they glow with a different shade of greenblue.. from Africa--where the like them too... on a skewer. 5Gal fish tank is big enough. and are easy to handle once you are used to them..
 

Pelagius

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They are by far my most fav.. and the biggest and fairly calm
not a nasty bite.. I took a blacklight bulb to work (Jerry's Pets)
and switched. with/bulb in th scorp tanks.. . sales of emperors took off.. IIRC they glow with a different shade of greenblue.. from Africa--where the like them too... on a skewer. 5Gal fish tank is big enough. and are easy to handle once you are used to them..
Hey Hakzaw1: great idea! I had a live reef tank for many years- I finished off the day light cycle with bulbs centered (not single wavelength) on 420 nm. The coral polyps glowed green and red-with some blue. Gorgeous!
 




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