Wierd white lines output from Blue-Ray

[Ufos85]

Hello everyone.
This is my first post here and im having a bit of a wierd problem with my blue-ray that I cannot explain.
From the output, I appear to get two vertical white lines on each side of the focused point, this applies both if
using glas or acrylic lens, but what bothers me is that these lines do not show up on camera at all, nor are they
appearing to be depending on flourising items as the white lines are visible on all objects by the eye.

Can it be because im running the laser at low output (only ~25mA before I get my safety goggles).

Unfortunately im leaving for a few days of vacation in about 8 hours, but would be very greatful for all help needed and can reply on wensday evening again if more information is needed.

I have attached a picture of the output that I took with my camera.
The right one of the lines is just actually barely visible with the camera too I just noticed when uploading the picture.
I hope my english isnt too bad

Best Regards
Ufos85

 

[brtaman]

Hmm,

That is pretty weird, are you sure its not your eyes playing tricks on you? Have you checked the diode window for any contaminants? I was getting some pretty whack artifacts from my blu-ray after I got a piece of the thread from the aixiz module onto the window. When i cleaned the window it all went back to normal.

Which diode are you using? 803t? Judging by your current 811t or ps3 diode? If its 803t (if they even begin lasing that low), try increasing the current to around 50ma, it will still be "safe" with responsible usage and might help your situation, otherwise I would recommend checking the diode window, just not with a bare eye, a magnifying lens plus alot of light will be needed for a through inspection (I couldn't see the contaminants on mine, without these tools).


Thanks
brtaman

 

[GooeyGus]

what you're seeing is an image of the actual die in the diode. This is caused by one of two things. 1) your diode is dead or (and more likely in this case) 2) you need to give it more current. at 25mA it's not even really lasing, hence the image of the die. Assuming it's an 803T diode, I would turn it up to a minimum of 50mA. This way it will still be relatively low power, but will be working how it should be.

 

[Kenom]

Wow! When I see a beam profile like taht I cringe. I know that either my diode is a zombie and is going to die VERY SOON. or it's not getting enough juice as gooey recommended. I would try more juice. if it dies. well then I guess you know which it was. heh.

 

[Ufos85]

Thanks for the quick replies!

The diode im using is the 803T.

I have checked the diod with a x25 microscope, and cannot see any contaminants, and Ive been really careful to avoid such.

However, I suppose it might be because of lack of current, I just found a few graphs on the forum telling me that I really shouldnt get any output at all at 25mA, so it might be too low for it to actually work.
I wished I had time to test it before leaving but really got to run now or Ill miss my vacation.

I will however check this the first thing I do when returning on wensday.

Have a great week everyone!

 

[brtaman]

Yeah if its 803t, then definately go up to atleast 50ish ma. That should solve your problem.



brtaman

 

[rkcstr]

I've seen this commonly, as GooeyGus suggested, with underpowering... but it does happen in damaged diodes as well. I think the die pattern is present at any time (ie perfectly normal), but just not very apparent at normal power levels, really only visible with a weak lasing diode (ie underpowered, damaged).

 

[Maven]

i have herd you can use UV sunglasses to protect from these lasers ... if i am wrong someone correct me ..

 

[GooeyGus]

i have herd you can use UV sunglasses to protect from these lasers ... if i am wrong someone correct me ..

You shouldn't use anything that isn't certified as suitible protection from lasers. The dye used in real laser safety glasses are meant to sustain 10 seconds + of direct contact from a high power laser without bleaching. I think that sunglasses are better than nothing, but dont think that you're super safe while using them

 

[Ufos85]

Hello everyone again.
Just returned from a mini-vacation, and I also have recived my safetygoggles now.
I have yet to turn up the output, but have so far noticed that with the goggles, the blue dot dissapear, but now I have a white dot left, and the two white lines if viewing through the goggles so I think its safe to say the white part are not caused by flouricing (terrible speller, but I hope you understand).

Will try later today to increase the input current enough to atleast get it to lase more and hope that will fix the problem, just find it wierd that a 405nm laserdiod output more wavelength than 405nm.

 

[Zom-B]

it is commonly known that violet diodes project yellowish auras around the beam. Sometimes more visible than other times.

This is indeed a projection of the laser die. I've looked at the die with a 40x microscope and the die looks transparent (slightly diffuse, but just slightly). When I power the laser very low, and still look through the microscope, I can see the sides starting to glow yellow. This glow increases to a maximum when the laser is about the lasing threshold current, and increasing the current after that point will not increase the glow intensity. Basically, driving the laser brighter will reduce the ratio of yellow/violet.

When the laser is underpowered such that the ratio of yellow/violet is worst, then focusing the lens differently will get the die neatly in focus (violet out of focus) and you can study the shape of the die perfectly.

In your image I DO see the white lines. It might be your monitor that's preventing you from seeing it (I know, for example, notebook screens all have the worst color representation of anything I know)

I pulled the image apart with paint shop pro and fabricated false color images in order to isolate these white lines

 

[Ufos85]

I have now tried it at a higher current, and not only does it shine better, the white lines appear to be gone, so guess it was acting more of a LED than a laser.
I am a bit worried thought even if its off topic of this thread, but I have set my laser to draw 35mA, which according to graphs, should be ~5mW before lens, but it appears to be alot brighter than my green 5mW laser, when using it on items that flourice, does this actually mean it output alot more than 5mW, or that some of the light that are absorbed both by green and 405nm, start "glowing" when absorbing 405nm and therefor get a brighter reflection in return? By "glowing" I mean reflecting back in another wavelength.

Here is a picture where the violet part of the laser isnt much brighter than my 5mW green laser, but when I point the 405nm on the green wheel of an RC-car, it glows _alot_ brighter than the green 5mW could never come close to in reflection.

 

[Zom-B]

Maybe you've got a 'Freak' diode (search for daguin's thread), although I can't tell for sure without accurate readings at multiple currents. Is your 5mW green actually 5mW, or is it a cheap ebay laser which are often underpowered a lot? Are the batteries fresh?

Just think about how bright it'll be when you give it 100mA

 

[Ufos85]

Maybe you've got a 'Freak' diode (search for daguin's thread), although I can't tell for sure without accurate readings at multiple currents. Is your 5mW green actually 5mW, or is it a cheap ebay laser which are often underpowered a lot? Are the batteries fresh?

Just think about how bright it'll be when you give it 100mA  

Im quite certain that the 5mW one is actually 5mW as Ive purchased it from a local store that only sell quality items, or atleast to my knowledge, and dont get me wrong, that one is bright aswell, but the BR one appears to be brighter.

However, is it possible that the driver somehow output more current to the laserdiod, than it use from the batteries? (as thats where im measuring), not sure how the driver work, but I know it drops the voltage atleast, its a rkcstr driver.

I mean that if the driver draw 35mA, the laserdiod get more? I dont think this should be the case but I could be wrong, and if not, is it safe to drive it at ~130mA like most appear to do here, or is it possible that it will die sooner as it starts lasing before the graphs barely show any output at all?

Sorry if this sound comfusing, its way too hot for my brain to work as it should but I hope you can understand what Ive written

 

[Chicxulub]

my BR is a verified 15 mw. When it's on a non fluorescent surface, it's a good bit dimmer than my 5mw Lyra. When it's on good fluorescent surface, it's much brighter than my Lyra.

I think your laser is operating normally.