665nm?

[erik]

Hello all

Been looking around a bit for lasers that can produce 665nm, but like with LED it seems hard to find. Does anyone know where I might find lasers of that wavelength? Preferably >100mW.

Thanks!
/Erik

 

[Trevor]

You have oddly specific wavelength requirements. I would expect an overdriven DVD burner laser diode to come in at around that wavelength - but that might not be controlled enough for your application.

Why do you need precisely 665nm? What amount of error or linewidth is permissible?

-Trevor

 

[daguin]

Laser diodes are "rated" for wavelength with a "range" (e.g. +-7nm) Also, as Trevor has alluded to, the wavelength will vary with temperature and current.

Peace,
dave

 

[erik]

Trevor;
Hm, “overdriven” ? How do you mean?
Line width as in the width of the light/spectrum produced?

I have been experimenting some time now with LED for growing plants, and lately been wondering about lasers and if that might be a even better way to go since from what I have seen they have a much more narrow spectra than what LEDs produce. 665 nm is this case is one of the main wavelengths needed for growing.

daguin;
Current I would have guessed, just like with LED but I had no idea that temperature affected the wavelength. Does wavelength vary all the time depending on temperature, or does it start going off at a certain point?

 

[Trevor]

Well, we run DVD burner diodes much harder than they are designed for - so, overdriven.

If you want to ensure long life out of these diodes while running them continuously, you might not get them up to 665nm.

A lot of companies make red LED's - those will generally be easier to work with and less touchy than laser diodes. Have you had limited success finding LED's that emit the wavelength you're looking for?

-Trevor

 

[erik]

Ahh, okay, I see..
I will keep what you have said in mind for future experimenting, but it is probably as you say not controlled enough. Need to invest in a spectrometer first in that case, and they do not come to cheap

I have been in contact with many hundreds of companies that produce both diodes and lamps, extremely hard to find any that can do exactly 665. Of all the wavelengths I need this is probably the hardest one to find. My current manufacturer got it to peak at 667nm, and that is the closest I have ever found for any (high power) LED.

 

[eexe]

Does it have to be EXACTLY 665 nm? What do you use for other wavelengths?

 

[erik]

It would work if the wavelength were a bit higher or lower, but it would not be optimal. To use for example 660 nm instead there would be about 10-15% less energy uptake in a plant.
But I think I will have to settle for 660 for starters, and take it from there if I get any good results.

In this case when my main interest just is measuring growth only blue of 480 nm is needed. Had a look at Google before and saw that its pretty available so no problem there at least.

 

[erik]

By the way...
Does anyone know where I can get appropriate lenses for splitting up light from a laser from a little dot to a rather big one? Kind of like the heads you get with some hand held laser pointers but instead of “i love you” or a star I need just a big blob of light

 

[Wolfman29]

Well, if you want it to be *really* diverged, just take lens off of the laser!

 

[erik]

I only own one laser at the moment and it does not seem like I can get the head of it without breaking the housing. Do you know about what angle of light it would give if I would take the lens off?

 

[Trevor]

You'd probably be looking at ~30 degree divergence, I think.

-Trevor

 

[Wolfman29]

^ He's got it.

 

[erik]

That might just be enough,

thanks guys

 

[Wolfman29]

Good luck! Let us know the results!

 

[Cyparagon]

I'm certainly no plant expert, but why use red at all? Google tells me that blue has a better absorption.