Specific wavelength LEDs

As far as light output, look for milliwatts. As far as wavelength, look for nano-meters. So a red LED might be 100 mW at 650nm.

Also take a look at diode lasers. If you search eBay, you'll find a bunch of LEDs and diode lasers.

Look at getting as close as possible 'off te shelf' and then look for optical FILTER. You will need to use the curve provided for the LED at the λ of interest and then compensate to get it where you want. For ex: if a 1 watt emitter is 30% down at 545 since it is tuned to 560, then you have to get (1/.7) watts into it (this may mean using two).

Then you put a filter in front of it and voile, finis.

Also, be careful about total radiated power versus the cone you actually are using.

If the filter is also a lens, then you can recover more power for the directionality you are interested in.

Hello Biggjoshie,

How "specific" must these wavelengths be? What spectral width? 1 nm? 10 nm? More? Less?

Depending on your application, spectral width is defined variously as the wavelength interval over which the magnitude of all spectral components is equal to or greater than a specified fraction of the magnitude of the component having the maximum value.

In optical communications applications, the usual method of specifying spectral width is the full width at half maximum, i.e., the difference between the two extreme values of the wavelength at which the intensity at the extremes is equal to half of its maximum value. This method may be difficult to apply when the spectrum has a complex shape.

Another, more general method of specifying spectral width is a special case of root-mean-square (RMS) deviation where the independent variable is wavelength, λ, and f (λ) is a suitable radiometric quantity.

The relative spectral width, Δλ/λ, is frequently used where Δλ is obtained according to some specific criterion where λ is the center wavelength.

Cheers,

-e

But in the scenario you describe, isn't the amplitude of the wavelengths he is talking about going to be seriously limited? I took a look at the λ's he was interested in and couldn't remember any diodes that produce these wavelength.s

So, if he wants power at these λ's, his power is going to be seriously limited.

Just a thought.

Hi Vermin,

Are you speaking strictly of laser diodes? If he requires narrow spectral widths at these wavelengths, he's gonna find it difficult (as you know) to find them in a laser diode. If his spectral requirements are more relaxed, appropriately-filtered LEDs (as others here have said) may fit the bill - but at the cost of considerably reduced efficiency.

No, I'm thinking of LEDs. It doesn't seem like I've heard of any that work at these wavelengths. And as you said, if you can filter them to get the correct λ, then power is going to be reduced significantly.

Perhaps a different form of illumination would be better to use.

I have looked at countless LED manufacturers and made many phone calls for information, and so far the closest I've come is to use phosphors. As for how specific the wavelengths need to be--I'm just looking for the most power out of the LED as possible at those wavelengths so I don't think any filtering will help, because of what I know, filtering just cuts out all wavelengths that don't match what you're looking for, and i need just higher flux outputs. I am however currently talking with phosphor tech which works with Georgia Inst. of Tech and they are semi interested in researching into possibly a new phosphor to use. Any further info from you guys would be greatly appreciated.

Hi Biggjoshie,

This outfit claims to be able to create an LED of any color by using fluorescent dyes in conjunction with an LED which causes them to fluoresce. Check out their LED-C products. (Their tag line: Designer LED-C™ Unveiled: Create Any Color LED In the Visual Light Spectrum) These LEDs may meet your requirements for color - as seen by the eye, not a spectrograph, which will still see the individual color components - but brightness is still a problem unless you're willing to go with an LED array. See if these folks have got what you need.

So at 545 and 560 nm, you're talking about yellow-orange light, right? If so, there are several diode lasers that produce these wavelengths. Try here on eBay, you might find what you are looking for.