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About spectrum width of infrared emitters and LEDs

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Member level 2
Jul 4, 2004
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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.

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.

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.

Please check this link you find IR diodes with less than 1 nm bandwidth
**broken link removed**

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