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belax
Joined: 04 Jul 2004
Posts: 32
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 05 Nov 2009 20:54 About spectrum width of infrared emitters and LEDs |
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I have few questions related to IR emitters and general LEDs too.
Let’s take for example IR emitter TSHF5210, produced by Vishay.
(Just in case, I attached datasheet to the post). This IR emitter has spectral peak of its emission at 890 nm.
1) Why does it have such a wide spectral width (about 75 nm)?
2) Why can’t it have narrower width, let’s say 10 nm?
3) As I understand this spectral-plot was obtained during constant current flowing through the IR emitter. Will the output spectral-plot of the IR emitter be the same for very short impulse (e.g. 70 ns)? If not, how will it be different?
I am asking all these questions, because in some applications I need narrow spectral-band. Diode-Lasers do have a narrow spectrum, but they also do have a heavy price? I am wondering, if by means of fast switching, the IR emitter will have a narrower bandwidth or the bandwidth will have spikier shape?
Thank you.
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ark5230
Joined: 29 Jun 2009
Posts: 188
Helped: 15
Location: India
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08 Nov 2009 19:13 About spectrum width of infrared emitters and LEDs |
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| No that is not possible. It is the characteristics of the materials used and the working conditions. You may resort to a cheap laser diode like arrangement, else use a optical filter in front of the souce with bandwidth. Please note narrower is the filter width that lower will be the available power.
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belax
Joined: 04 Jul 2004
Posts: 32
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09 Nov 2009 11:30 Re: About spectrum width of infrared emitters and LEDs |
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About laser diodes I understand.
I just wanted to consider to use IR emitters (not Laser ones) in ND:YAG rod side-pumping scheme . But it seems will be very low efficient solution, because of the broad-bend spectrum.
Thank you.
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ark5230
Joined: 29 Jun 2009
Posts: 188
Helped: 15
Location: India
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