IR Filter

[Southpaw]

hey i just want to know how to make a cheap homemade IR filter for my greenies. I hear that developed film can, but im not sure. thx

 

[ElektroFreak]

I've heard that developed negatives work, but I'm not sure if they actually do. After investigating how to make a homemade filter I came to the conclusion that the best thing to do is just buy one. They're fairly cheap and easy to find once you know what to look for. Schott BG38 absorption glass is the best IR filter material for blue or green lasers. You can find optical filters made out of it almost anywhere those types of things are sold.

Check my signature, it has a link to some BG38s (12mm for $10), or you can get them from Novalasers.com for the same price.

 

[kendon]

a piece of film, in particular a slide-film, not exposed and developed (and so deep black, like if you take a picture with your lenscap on the lens) will work as an ir filter, but in the sense that only infrared light passes through it. this is not what you are up to.

you can use it to make ir pictures of the world, looks quite amazing. just point your tv remote at your camera, when you see the led blinking that means your cam does not have an ir filter (in this case that would be one that blocks ir). tape the slide in front of your lens and you are good to go! the (blue) sky will be deep dark in the pictures, with white clouds. surprisingly green will be bright white as long it is from plants, as the chlorophyl in the leaves emitts very much ir light (IIRC).

http://www.photoaxe.com/wp-content/uploads/2007/03/infrared2.jpg

i made some of these myself (not the one in the link, that seems to be professional). just get a non-exposed slide, tape it in front of your digicam and wait for a sunny day (obviously you need a lot of light, since the dark slide is really dark. but it works!)

 

[Razako]

Don't try to make a homemade IR filter. Just buy one for 99 cents from optotronics.

 

[ElektroFreak]

Don't try to make a homemade IR filter.  Just buy one for 99 cents from optotronics.

Optotronics filters are made of KG2 glass. BG38 is far superior to KG2 in that it allows more visible light transmission (90%) and less invisible light transmission (.01% at NIR,IR, and UV). That explains the price.. KG2 allows up to 50% of 808nm and 10% of 1064nm light to pass.

 

[vegasf6]

Bump for a super old thread. Can anyone point out a good source, (up to date) for an infra red filter I can use while measuring power with my LPM? Can I use the same one for green, red, UV, 440nm 405nm etc?
I don't expect it would be a good idea for 808s or IR lasers :0

 

[MarioMaster]

I have IR filters here at Radiant - Small IR Filter

They are coated for green, but would still work for most other applications albeit with a bit less transmission.

Keep in mind that 650, 635, 405, 445 diodes and whatnot are all direct diode lasers and do not emit IR.

IR filters are needed for DPSS systems like 532, 473, 671, 593.5, and 589nm.

 

[vegasf6]

Direct diode lasers don't emit IR? Well that's good to know.

Are your filters BG38 or KG2 glass as mentioned above? Or another type?

Thanks for the link by the way.
VegasF6

Oh P.S. I just promoted your website earlier today
http://www.candlepowerforums.com/vb/showthread.php?304436-Looking-for-my-first-laser-Wicked-lasers