808nm optics - having trouble finding them

[gearboxtech]

Hello all, new member throwing out a random blurb in the hopes that I can be pointed in the right direction.

I'm building an IR illuminator for night vision. It'll be based on the 808nm wavelength, using the cheap to18 diodes until the optics are sorted. The idea of the project is to build something reasonably cheap for proof of concept without having to buy ridiculously overpriced (and somewhat crap) IR illumination gear.

The only issue I am having is sourcing optics. I'm after somewhat decent coated biconcave and biconvex lenses. If I cannot get either, then a decent source of the same lenses in ground glass would be fantastic. Unfortunately, ebay and aliexpress have plenty of interesting stuff out there but the months of waiting or expensive postage for potentially dubious products.. sigh.

Lens size does not bother me too much, I need to see what is out there more than anything.

Any help would be appreciated

Since the questions will inevitably pop up, I'll be using analog sony 1/3" CMOS CCTV chips with the ICX673 Exview HAD II sensor (very sensitive to IR wavelengths) to view the beam when testing and for IRNV. The image will be displayed on a 7" 1024x768 LCD in the field and a large LCD in the workshop.

I have eye protection, it's the first thing I ordered. I purchased a pair of eagle pair OD6+ 600-1100nm safety glasses. That'll well and truly cover me in the 650nm and 808nm wavelengths I'll be using. http://www.ebay.com.au/itm/281596763475

 

[Apocalypse]

Welcome to the forum!

Are you trying to build something like a flashlight for illumination? Wouldn't IR LED's work? Also why do you need coated lenses? I don't imagine losses at 808nm would be that big through ordinary glass. IR diodes are also really cheap so you can just look for a more powerful one than that 300mW version. As for cheap optics, you can probably ask DTR here to see if he has some projector optics left and see if any match your description. If not, I think Ebay would be the best way to go.

 

[gearboxtech]

Cheers, happy to be here. I've been trawling here for info for a while now, figured it was time to finally sign up!

Laser > LED when it comes to range

A torch IR illuminator would be what I am designing. I'm aiming for at least 50m at the moment.

To get that I need to minimise losses in the design where I can. To do that, coated would be optimal but good quality uncoated lenses are what I'll probably end up using

Any good sources for lenses would be appreciated!

 

[Apocalypse]

One thing I'm worried about is that the laser could be too focused compared to an LED. Since it is invisible, there will be no blink reflex and it could do damage to the eye if you accidentally point it at someone. Where will you be using this for night vision?

Looks like it is a 5.6mm diode here. Is it inside a module right now? You could probably use the 3 element lens found here and just adjust the focus. I'm not sure how wide you want the beam to be at 50m but I think this might work. You could then just put it inside a host and have an adjustable focus laser.

 

[gearboxtech]

Good points on the safety aspects. Yes, it's for night vision. Homebrew style but hopefully no less effective

I've planned to have a cone on the end of the illuminator to catch any stray beams for those beside me and the few other users of it will know to not dick around with it. As well as this, it'll be used on farms and forests, not around residential areas.

Trust me when I say that I respect the nature of NIR. The single most expensive thing thus far has been the safety goggles OD6 Diode Laser Goggles 808nm 810nm 904nm 980nm CE EN207 208 AU NZ Certificated | eBay

I've been in contact with DTR and will be ordering some stuff from him.

I plan to machine my own diode+lens housing from copper stock and the sleeve heatsink from aluminium stock but those copper and large heatsink modules that DTR sells are looking pretty good for something to test with!

You're correct, the diodes are 5.6mm to18 bare diodes. I do not expect much from them, they are cheap bulk diodes. As with my LED lighting builds, I play with bulk LED chips, I build with known chips of a binned quality

I'm aiming for a 3m beam width at 50m. I'm not certain how sensitive the CMOS sensor is to IR. It'll be hooked up to a bushnell 6-24x50 ET6245FG scope, so the optics should be able to handle it

 

[steve001]

Hello all, new member throwing out a random blurb in the hopes that I can be pointed in the right direction.

I'm building an IR illuminator for night vision. It'll be based on the 808nm wavelength, using the cheap to18 diodes until the optics are sorted. The idea of the project is to build something reasonably cheap for proof of concept without having to buy ridiculously overpriced (and somewhat crap) IR illumination gear.

The only issue I am having is sourcing optics. I'm after somewhat decent coated biconcave and biconvex lenses. If I cannot get either, then a decent source of the same lenses in ground glass would be fantastic. Unfortunately, ebay and aliexpress have plenty of interesting stuff out there but the months of waiting or expensive postage for potentially dubious products.. sigh.

Lens size does not bother me too much, I need to see what is out there more than anything.

Any help would be appreciated

Since the questions will inevitably pop up, I'll be using analog sony 1/3" CMOS CCTV chips with the ICX673 Exview HAD II sensor (very sensitive to IR wavelengths) to view the beam when testing and for IRNV. The image will be displayed on a 7" 1024x768 LCD in the field and a large LCD in the workshop.

I have eye protection, it's the first thing I ordered. I purchased a pair of eagle pair OD6+ 600-1100nm safety glasses. That'll well and truly cover me in the 650nm and 808nm wavelengths I'll be using. OD6 Diode Laser Goggles 808nm 810nm 904nm 980nm CE EN207 208 AU NZ Certificated | eBay

Give Edmund Optics a look over http://www.edmundoptics.com.au/?site=AU&countryid=13&_ga=1.10850996.165698216.1441915846

 

[gearboxtech]

Cheers for that

I discovered edmund optics earlier in the week. Given the crappy AUD>USD exchange rate, I'm holding off on buying pro optics until I know exactly what I need. I also managed to find a few suppliers of older edmund optic glass (uncoated) but once again, the damn exchange rate.

In the end, I've purchased assorted bargains of good quality optical lenses of differing sizes, types and focal lengths to play around with different designs.

I also purchased some stuff from DTR https://sites.google.com/site/dtrlpf/home

For shits and giggles, I've also decided to build a large (huge heatsinks) LED illuminator based on 10x3W epistar 850nm LEDs - should have a lumen output of 120lm/w so 3600 lumens. I've got quite a few lenses of varying designs, from 5 degrees to wide 180deg glass domes that will be suitable for these chips but I am curious of how smaller footprint I can achieve. I've never built distance LED arrays before so I'm tempted to build a custom mirror reflector for them but I am quite shit at cutting glass, not enough practice I suppose Usually I just polish the heck out of aluminium but I would like to see the lumen difference on a focus point at range.

Will be interesting to see the comparison but I am sure the lasers will prove a muuuch more efficient design in both lumens/w and lumens/kg but is clearly dangerous if not used correctly. That said, so is what it'll be attached to.