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FrozenGate by Avery

I am looking for a source of 820-860nm diodes.

L

LaserGuns

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I have a thread going in the general section, but I was suggested to go here with regards to my IR diode questions.

I'm looking for an IR diode in the 820-860nm range and in the 30-50mw range.

The purpose is for a pointer (I know it is invisible to the naked eye:yh:) so I need a fairly straight beam. In the other thread I was told I was looking for a diode with FAC. Does anyone know where I can find such a thing?

Also what kind of focusing lens would I need?

Thanks!
 





:confused: 780nm more invisible then 820-860nm? Do you mean at 30mW 820-860nm might be visible whereas 5mW (at 1/6 the power) wouldn't be even tho its 780nm? 808nm is visible to my eyes (haven't tried as low as 5mW tho).
 
Ok not confused anymore. :san:
You could check how you night-vision picks up a TV remote, 940,950nm LED is typical for them.

Found this quite awhile ago $6.85 980nm 50mW 5V Laser SKU: S006191. I would think its unlikely to have a FAC.

O-like use to have a 980nm @ 65mW for sale, been meaning to ask them if they could still get it & if it has a FAC / what the divergence is.
I know member aryntha owns one according to his signature.

I saved these details
"980nm laser torch 65mW"
Product code: OLLP980
Our Price: $ 38
Shipping Fee: $5.00
Wavelenght: 980nm
Outpower: 65mW
Dimension: 18*130mm
Power source: 2pcs*CR2 battery

Email:O-like@live.cn
MSN:O-like@live.cn
Yahoo:Olike_Vivi
Skype:O-like
Link to 1st thread in general section so it never gets lost.
 
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Thanks.

These 980s seem to be a lot cheaper than 850s. Especially that $6.85 one... What's up with that???

I'm not sure why I should use 850nm over 980nm, if I even should at all. Looking up the specs for military IR lasers, they are all in the 820-860nm range, so they may just pick up the higher frequency light better. At $7 I may just pick one up and see how well it works...

About the FAC, I haven't even really been able to find one at all. I've spent hours combing through various sites, everybody makes them, but they just sell them to giant manufacturing companies... I'm starting to wonder just how bad it would be to not use a FAC.
 
the thing about 808s idk if it applies for 850s is that there just on the edge of visible spectrum so there not really ir just very very very dim :D
 
Hmmm, I did a little poking around and found this chart.
nvdspectrumrange.jpg


Looks like I want to stick the the 850nm range!
 
Some wavelengths are more expensive for lasers. Kaidomain sells alot of very cheap stuff from Hong Kong like dealextreme.com. The quality can suck or be ok. Still seems cheap for that laser tho.

I recall someone posting a source for FAC lens but it might have been ebay.

Without a fac it won't project a beam but more of a line.
Looking at the specs for the 850nm, 30mW from ThorLabs again:
(I'm substituting Vertical & Horizontal for Parallel & Perpendicular)
Characteristic ......................................... MIN. TYP.. MAX. UNIT.
Beam Divergence (FWHM) - Vertical ...... 7 .... 8.5 .. 12 ... deg.
Beam Divergence (FWHM) - Horizontal .. 23 .. 30 ... 35 ... deg.
Fast Axis is Horizontal & its spreading out at ~30 degrees
Slow Axis is Vertical & only spreading out at ~8.5 degrees
A normal lens focuses Vertical & Horizontal by the same amount & one would always be spreading out more then the other.
The right Fast Axis Correction would bring Horizontal down to the same 8.5 degrees & then you can use a normal lens to focus into a beam.

Others know more about IR diodes & lenses but they just haven't showed up yet. :can:

~EDIT~
Thats a great chart! Where did you locate it?
No wonder they use 850nm. Its too bad tho, 980nm seems like it may be easier to find & less expensive.
 
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The chart is actually from a PDF about measuring NV performance. Here I didn't read through the whole thing, but I 'll have to save it and go through it later.

I looked at some other laser spec sheets, and it looks like for red diodes, it is more common to see around 8.5:15-20 compared to 8.5:30 for the IR ones. So a red diode is about 1/2 to 1/3 as rectangular as an IR one (On average).

I guess I'll keep looking...
 
Well, I sent a inquiry to Blue Sky Research about their "virtual point laser diodes" Apparently they have correcting lenses already installed in the mirrors... They are a little pricey, at $150 each with a minimum order of 3, and a lead time of 4-5 weeks.

That is for the 830nm diodes at 50mw. Apparently they have "B pin-out" and according to their sheet, that just means the current is going in the opposite direction as "A".

I think $150 is reasonable considering I won't have to deal with the FAC. The only hitch is that I only need two, and the min order is three. Its not THAT big of a deal, I may just end up ordering four and have enough for two devices. Also, if anyone is interested in getting a few, just let me know.

Unless I find a better solution, I'll probably be ordering in the next week or so.
 
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