Adding an infra-red filter?

[RichiH]

I got a cheap green laser from DX to get a feel for the whole thing. As they have a warning that there is no IR filter in any of their lasers, I am wondering

a) if that is needed. Any IR emitted should not be pulsed afaiu
b) if I can easily hack an IR filter into my laser. If yes, what is the best material and where do I get it
c) if working with goggles, do I have to worry about the IR bypassing the green filter?

I was not 100% sure which sub-board to post to. As the probable answers will most likely end up in /me modding my laser, I decided for this forum.


Thanks!

 

[ElektroFreak]

I got a cheap green laser from DX to get a feel for the whole thing. As they have a warning that there is no IR filter in any of their lasers, I am wondering

a) if that is needed. Any IR emitted should not be pulsed afaiu
b) if I can easily hack an IR filter into my laser. If yes, what is the best material and where do I get it
c) if working with goggles, do I have to worry about the IR bypassing the green filter?

I was not 100% sure which sub-board to post to. As the probable answers will most likely end up in /me modding my laser, I decided for this forum.


Thanks!

Whether or not you need one depends on the power output of the laser and your personal taste. An IR filter just guarantees that the output is 532nm green only. With higher powered lasers (>100mW), the IR leakage can be significant enough to pose a minimal safety hazard.

The best material for IR filters is SCHOTT BG-38 or BG-39 absorption glass. Novalasers sells small filters made of BG-39 that are AR coated for 532nm. Once you add shipping, they are a little costly so you can also get them in quantities of 10 from snoctony here: http://cgi.ebay.com/10-pieces-IR-Fi...5|66:2|65:12|39:1|240:1318|301:0|293:1|294:50

If using BG-38 or -39, less than .01% of IR will make it past the filter. Here is a transmission datasheet for BG-38: http://www.optical-filters.com/bg38.html

 

[accuteoptical]

An IR cut filter can be used for you.It can block IR filter and pass visible light.

 

[Bionic-Badger]

The irony will be that you'll probably spend more on the IR filter than you did the laser pointer from DX.

 

[phoenix77]

IR filters are $10.00 from LASERGLOW