Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers



Confirmed cheap multi-line 980nm/490nm pen

Blarg King

New member
Joined
Oct 18, 2013
Messages
1,060
Points
0
Re: Possible cheap 2-line 980nm/490nm pen

The one I got is 980 nm. Outside of GITD stuff I can definitely see a faint blue dot coming from it if I let my eyes adjust to darkness.

Weird that IR causes fluorescence when its on the opposite end of the spectrum from UV.
 



Atomicrox

Well-known member
Joined
Jun 22, 2011
Messages
2,432
Points
83
Re: Possible cheap 2-line 980nm/490nm pen

Mine is 980nm as well, what I meant is that I tested this one and two other IR's, for the sake of completeness.

Glad to know you also have the second line. Just take care not to stare at it up close without an IR filter.
 

rhd

New member
Joined
Dec 7, 2010
Messages
8,492
Points
0
Re: Possible cheap 2-line 980nm/490nm pen

Confirmed.

The second line is approximately 490nm.

I couldn't pick it up on my spectrometer, but dark adapted eyes could pick up the dot. They could also pick up the secondary dot created when the laser was shined through a cheapo 1000 l/mm diffraction grating.

I awkwardly tagged the two dot locations, and then turned on the lights, to compare to the dot locations produced by doing the same thing with a 495nm diode laser. Almost exactly the same positions, so the 490nm theory seems well founded.
 

Atomicrox

Well-known member
Joined
Jun 22, 2011
Messages
2,432
Points
83
Re: Possible cheap 2-line 980nm/490nm pen

I'd +rep you if I could :)

You sir have a good pair of seeing balls! I can't catch the first order diffracted dot on the wall at all.
 

Blarg King

New member
Joined
Oct 18, 2013
Messages
1,060
Points
0
Re: Possible cheap 2-line 980nm/490nm pen

Yeah being careful with it until I get my IR blockers. Its a bit scary have a laser with a non visible beam. I measured it with my LPM and its 60 mW, so not a death ray at least. Should make filtering out the IR easier.

Once I get them I'm going to try chilling the laser with a TEC to see if temperature affects the 2nd line.
 

Atomicrox

Well-known member
Joined
Jun 22, 2011
Messages
2,432
Points
83
Re: Possible cheap 2-line 980nm/490nm pen

I look forward to seeing your TEC results.
 

The_LED_Museum

Active member
Joined
Nov 1, 2006
Messages
512
Points
43
Re: Possible cheap 2-line 980nm/490nm pen

I don't have a TEC, but I'm willing to pop my laser in the freezer and see if the suspected 490 nm laser line increases in intensity (brightens) or shortens in wavelength.
 

rhd

New member
Joined
Dec 7, 2010
Messages
8,492
Points
0
Re: Possible cheap 2-line 980nm/490nm pen

I don't have a TEC, but I'm willing to pop my laser in the freezer and see if the suspected 490 nm laser line increases in intensity (brightens) or shortens in wavelength.
I feel dirty and sick even saying this.... but what do we expect the impact of pot modding to overdrive this unit would be on the 490nm line?

(In reality, I wouldn't actually pot mod, but rather remove the drive entirely, and over-drive the diode from a bench PSU).

EDIT: Do we expect this second line to occur with all 980nm diodes? Multimode included? Anyone have a 4W C-Mount 980nm ?
http://www.ebay.ca/itm/C-mount-Package-High-Power-4000mW-4W-980nm-Infrared-IR-Laser-Lazer-Diode-LD-/120921397175?pt=LH_DefaultDomain_0&hash=item1c277a17b7&_uhb=1
 
Last edited:

Atomicrox

Well-known member
Joined
Jun 22, 2011
Messages
2,432
Points
83
Re: Possible cheap 2-line 980nm/490nm pen

I feel dirty and sick even saying this.... but what do we expect the impact of pot modding to overdrive this unit would be on the 490nm line?

(In reality, I wouldn't actually pot mod, but rather remove the drive entirely, and over-drive the diode from a bench PSU).

EDIT: Do we expect this second line to occur with all 980nm diodes? Multimode included? Anyone have a 4W C-Mount 980nm ?
C Mount Package High Power 4000mW 4W 980nm Infrared IR Laser Lazer Diode LD | eBay
That's exactly what I was thinking. If this isn't a "bug" of this diode we might be able to get a few hundreds of uW from a higher power. If this is confirmed I'm surely going to build a handheld with an IR filter permanently attached (or perhaps a dichro/beam stop - that power's gotta go somewhere).

I noticed the second line seems to flicker a bit. Maybe the harmonic lases better at a very specific temperature/wavelength. Perhaps we could use a TEC to stabilize temperature and optimize the second line instead of just cooling it.
 

The_LED_Museum

Active member
Joined
Nov 1, 2006
Messages
512
Points
43
Re: Possible cheap 2-line 980nm/490nm pen

...Weird that IR causes fluorescence when its on the opposite end of the spectrum from UV.
Not wierd; what you're probably seeing is anti-Stokes fluorescence.

In this type of fluorescence, a longer wavelength causes fluorescence to occur at shorter wavelengths. Some types of chemo-optical IR detector cards (specifically, the kind that glows green when irradiated with NIR radiation) exhibit anti-Stokes fluorescence.
 
Last edited:

Sigurthr

Well-known member
Joined
Dec 11, 2011
Messages
4,374
Points
83
Re: Possible cheap 2-line 980nm/490nm pen

IR can also cause de-excitation of glow in the dark (not fluorescent) materials. If you find one of those cheap plastic ceiling stars that glow once charged up, a strong NIR/IR source can discharge areas causing them to rapidly darken and remain dark after irradiance.
 

The_LED_Museum

Active member
Joined
Nov 1, 2006
Messages
512
Points
43
Re: Possible cheap 2-line 980nm/490nm pen

Here is an example of NIR radiation activating the phosphor of an anti-Stokes IR detector card:



After 3 minutes, you'll see the IR detector card being irradiated by NIR laser radiation at ~808nm.
 

zyxwv99

New member
Joined
May 6, 2013
Messages
178
Points
0
Re: Possible cheap 2-line 980nm/490nm pen

I've never heard of fluorescence being limited a specific wavelength range or direction. For all I know, radio waves could cause something to fluoresce in microwaves. I'm not saying this is the case, just that from what I've read on how fluorescence works, I can't see any reason why it shouldn't.
 
Joined
Apr 26, 2010
Messages
4,177
Points
83
Re: Possible cheap 2-line 980nm/490nm pen

Well this escalated. I'll grab a couple cheap pens off eBay.

Considering a 1W diode or something like that too.

As for doubling the 980nm using Yb fiber. Getting the Yb fiber will be the easy part. And that's saying something...
 
Last edited:
D

Deleted member 16589

Guest
Re: Possible cheap 2-line 980nm/490nm pen

Weird that IR causes fluorescence when its on the opposite end of the spectrum from UV.
whats even weirder is if you hit Zinc sulfide glow powder with light and then hit it with an IR laser it will glow bright for a sec then fade to dimmer than the surrounding powder. I found this out wile playing with a green laser that leaked IR. It does not work with strontium aluminate though.

also for anyone who needs a few IR filters I have some 7mm diameter ones
http://www.hoyaoptics.com/pdf/CM500.pdf.
 




Top