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Thread: May start a question for the day thread...

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    Default May start a question for the day thread...

    I have a whole host of questions I've been saving up and maybe it's time to start throwing out one a day. I understand they do sometimes give people pause to have to think about an answer so here goes:

    Laser diodes emit light at very specific frequencies i.e. 532nm, 640nm, 473nm, 405nm etc. Yet, there always seems to be concern for, and measurement of, or talk about "escape from the case", of infrared which... to my understanding... is invisable light (frequency) up past the 700's. (I'm not geeky enough to know the actual frequency.)

    If a laser is only supposed to be producing a specific frequency, then how are we getting infrared from everything and... what is the average percentage of the visable color versus the presumably more dangerous invisable infrared that's being emitted?

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    As far as I know the IR problem only exists with DPSS lasers because they use IR to produce the visible wavelengths. Someone can elaborate on how this is done asI will ust muck it up, but the basic set up is an IR diode at 808nm hits a crystal optic that changes it to 1064nm, then that hits anohter optic that "doubles" it to 532nm. I think 473 uses 808 to 946 or 947 to 473 (could be way off here). You want to have an IR filter at the end of the beam path before the final aperature to keep any IR that might have passed through the system inside the laser head.
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    No problem for direct diodes lasers.

    I can't wait for this to be a problem of the past once we get access to direct green diodes!

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    What I want to know is this. When I change the channel on my TV, it only takes one IR to do the work. What happens to all the other IR's that are emitted in to the room?
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    Quote Originally Posted by dnar View Post
    What I want to know is this. When I change the channel on my TV, it only takes one IR to do the work. What happens to all the other IR's that are emitted in to the room?
    if you are asking why other sources of IR don't mess with your TV its because the remote is sending pulse codes via the IR... so random IR sources are probably not going to send the same/similar codes to the TV so it just ignores it

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    Quote Originally Posted by flecom View Post
    if you are asking why other sources of IR don't mess with your TV its because the remote is sending pulse codes via the IR... so random IR sources are probably not going to send the same/similar codes to the TV so it just ignores it
    LOL, I know how IR carriers and coding works. It was a joke.

    Like sperm, it only takes one IR "particle" to do the job, what happens to the rest? Do they bounce around the room until they die?

    Sorry mate, sometimes my humor is too subtle and/or dry.
    Last edited by dnar; 05-03-2011 at 20:32.
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    Quote Originally Posted by dnar View Post
    what happens to the rest? Do they bounce around the room until they die?

    i think i have prooved that energy is not lost, it is just converted to another form of energy (this theory would have given my a nobel prize, but someone else beat me to it). So all the channels you have changed during the last 10 years, still bounce around the room in some form or another.

    it might be a good idea to open a couple of windows and let them out
    "its called character briggs..."

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