Red diodes and collimators.

[kl79]

Don't speak to me about laserwaves...

Marco's set are not free for sure...but we speak about a quality product !


Edit : I don't want to say something bad about laserwaves products, but here, we speak about "parts" not "assembly parts"
(may my english speaking is not very good, sorry)

[shrad]

laserwaves are quality modules, and their support is quality

there will always be a difference between commercial quality (which is great from laserwave), and a custom made product made available to the public because of its excellence

I agree 30€ is not cheap for a collimator barrel and a lens, but the next good alternative is aixiz + lens27, and on the other side you have thorlabs products which are in the affordable range for some top quality material

If I was to choose between marco's collimators and a lens27 in an aixiz housing, I'd go for marco's for sure, especially for opnext diodes

[andy_con]

has anyone used/tested marco's stuff? or are we taking his word for it?

[ElektroFreak]

What I want to know is how we are concluding that lens27 (or any collimator for that matter) is limited to no better than ~1.5mrad? Collimating a single-mode diode has the advantage of extremely low divergence since the initial beam diameter is large. Also, since the light emission from a LD comes from a microscopic point source, the beam diameter is "expanded" many times just in the trip from the diode facet to the first lens. This expansion results in some of the lowest divergence figures I've ever seen when compared to gas and DPSS lasers when using single-mode diodes. Obviously multimode diodes are a whole different story, though.

[kl79]

I own 4 lens 27 in my red setup, sure they are great, I have not measure divergence, but the spot is thin ( 1.5x2mm ?) and divergence is acceptable.

And I'm on the way to build another quad setup with two marco's set (640nm, 150mW) and two lpc815 with marco's colimator and driver.

[mccarrot]

What I want to know is how we are concluding that lens27 (or any collimator for that matter) is limited to no better than ~1.5mrad?

Thats what the datasheet says. And I think if a company like Roithner makes a datasheet whats the point about lying for a worse number?

[p1t8ull]

With the LENS27 in front of quite a few different SM DVD diodes I saw ~1mR and mostly <1mR.
A good thing about these if using them in a multi setup is the lens element is bonded to the M9x.5 alu threaded holder, so with a bit of PTFE on the threads you have zero movement possibility.

Marco, any pictures of your tube/lens assemblies in pieces please?

[ElektroFreak]

Pretty much any single-mode diode should be able to achieve well below 1mrad through just about any collimation assembly. This is because of the beam expansion that occurs prior to the output optics. Better optics will give more transmission and a better far-field beam profile, but divergence should be pretty much awesome in all cases.

[hobbybob]

lens 27 = 1.5 mrd , why would you want less. ?
all the greens and blues out there are about 1.5 mrd ,so it makes a good match then .
i use lens 27 on my 642nm and that more like <1 mrd so why they quote 1.5 on the data sheet i dont know

It's also the beam profile that counts, especially if you want to built a quad or 6 or 8 fold setup with diodes.
If a lens gives a nice 1,2x2mm beam or it gives a dot of 3x3 you will notice this when you are beamstacking and knife-edging all the beams together. Beamprofile is something different then divergence, but for building a quad also very important.

[RedlumX]

I'd like to know more detailed data of various lenses; I got data sheets only of the Roithner lenses (Lens-27 in particular), and of course of the (expensive) Geltechs of Thorlabs, but am lacking any data of most of the lenses that are popular here (Aixiz, 650-G-1) etc. In fact, there is much more to say about a collimator lens than just efficiency and beam divergence.

For optimal results, the lens must be matched to the particular diode and as such one needs to know the NA value, focal length and so on. I had complaints about the beam quality of my single mode lasers, and this was due to the fact that the Roithner Lens-27 I used is well-matched to ordinary DVD diodes, which typically have a fast opening angle of like 17 degrees; but it is not well-matched to the 642nm Opnext HL6385 I use, it leads to all sorts of spill-over diffraction effects, Airy rings, etc. In some cases the beam is pretty horrible and not well suitable for holography. Thus I am looking for lenses optimized for the HL6385 diodes (which have a fast opening angle of 23 degrees, ie, a larger NA).

I was reading here and there (LPF, that is) about various kinds of lenses, such as the 650-G-1, but couln't find anywhere reliable data such as the NA value and focal length, etc. Without these an optimal design is just a gamble. Does anybody have spec sheets or recommendations for other lenses?

Thanks,
R.X.

(similar post at LPF)