Quick question about 9mm 808nm diodes...
Is the beam emitted similar to the diode bars or to lets say a phr's beam? I have two 2w 808 diodes and would greatly appreciate any info regarding the beam shape! Thanks!
They have a single chip (also if more large than a PHR), so the shape is basically the same of any other single diodes, not like a high power bar.
Except if you have a diode with integrated FAC, that gife you a better shape.
You can safely see the shape, directing it against a white (non reflective, a piece of polystirene is ok) surface, powering them at reduced power, and looking it through a camera, webcam or surveillance cam ..... they see IR too.
If a high-powered multimode diode (like a 1W IR diode) doesn't have FAC (fast-axis collimation), you can use a cylindrical lens to perform the same function, but using an external lens will always increase the overall bulk of the assembly.
Here's what a FAC lens looks like on a c-mount:
You can see that there is a piece of glass fiber glued across the face of the diode. This acts as a cylindrical lens to collimate the fast axis of the diode.
All multimode diodes emit a rectangular beam, yes. I've never seen a diode of any wavelength over 500mW that was single mode. Most diodes over 250mW are multimode.
Hello, Ive just this second signed up to LPF, so i don't yet know all that much about lasers. i purchased a 9mm 1W 808nm LD off ebay, when i got it out the pack and powered it up, i noticed that the beam diverges or opens up quicker one way than it does the other, like a rectangular output. i have since discovered that it is a multimode diode (i have only ever owned "single mode"? diodes). can i buy any old FAC lens or does it have to be matched to my LD? and do i still have to use a "spherical"? lens as well? my knowledge of optics isnt great... incase you hadn't noticed :-(
Any help would be greatly appreciated .
If all you want to do with the 1W diode is make a burner, you can use an aixiz acrylic lens. Get it close to the diode face, and you will be able to get a burning point a few inches in front of the laser. You will not be able to produce a beam this way, with these multimode diodes you must correct the fast axis separately with a fac or cylinder lens, and then collimate. You would need to experiment with different lenses, viewing the results with a video camera so you can see the IR. FACs can be difficult to find, I don't often see them on ebay, for instance.
Thank you for the help .
i have got this burning with a normal glass AixiZ lens before but i wish to collimate the light. FAC lenses are not exactly cheap, i have seen a few of them on ebay everynow and then. i think the seller is a member of LPF too, "hesc-photonics" (from memory). i can't really offord to buy several and try them all out :-/. maybe its worth buying a diode that already has the FAC lens. do you know roughly how much a 80mW continous/ 240mW pulsed 650nm laser diode is worth (5.6mm, short closed-can)?
Thank you.
FAC is not needed in a green build. Just place crystals directly in front of diode. The optics would then come after the crystals. Usally a concave converging lens sitting directly on top of the crystals followed by a plano-convex lens to focus it.
I really hoped someone would say that. i watched a couple of videos on youtube and there appeared to be no FAC lens... that will make it cheaper, if i ever find some crystals that are within
my budget! whats the difference between nd:yag and nd:yvo4?
will this lens work to collimate the multimode diode?
PRECISION PCX CYLINDRICAL LENS 20MM X 12MM X 20MM FL - Surplus Shed