Prisms for 445nm diode front surface knife edging

[lasertack]

Don't think we really need the macro-shots for that... lookie a li'l closer..

Attachment 31431

..yes, the macro-shots will help show-up edge quality - which, yes, is important, but a different 'issue' vs a chamfered-edge (..as opposed-to a razor-sharp edge..) Still, looks-like even Kv uses at-least somewhat chamf'd prisms -

Attachment 31432

.. so, perhaps it will not prove to be that much of an issue.. in any case, we should-see some efficiency-gains over mirror-edging.. whether these will prove to be yet another 'game-changer', is TBD, but... at least these prices are making it 'reasonable' to-explore...

@ Alex - just-curious if you've actually built these into a multi-watt knifed-rig, and, if-so, what kind of efficiency did you see vs mirrs? Yes, it's understood that 'choice of lens, diode-current', etc, etc are all 'factors', but even so, it would be easy to say, set-up a rig with, say, 4x diodes, each putting out 1.2W of 445, post-lens, and off a 4-up knifed mirror-rig, you got "X", when-summed (..this also assumes that, yes, you are an ace at knifing.. ...And again, same test-conditions, only using these prisms, and you got "Y", when summed... something like that.. ..Any real-world 'case-study' data like that?

..Not trying to appear 'critical' or anything, but, ya know.. these are the sorts of questions potential-buyers of 50-60 pieces of practically-anything, tend to ask.. And, while this sort of 'minutia' may-not be too 'relevant' for those building 2-4- ..maybe even 6-bangers, for those doing 10+ up's... 'chamfered vs un-chamf'd' is at the very-least, something you wanna know, going-in..


cheers..
j

Hi Jon,

you´re welcome to ask me whatever you want and I´ll do my best to give you the informations you need.

To be honest, I built no setups with this prisms. I tested the reflectance and the coating. I gave some of this prisms to a friend and he built two 4x 445nm diode modules. Unfortunately I wasnt allowed to make some pictures as the design of the module is new an he doesnt want this design get copied.
What I remember is, that the diodes were from an M140 projector, running @800mA, putting out about 1050mW with aspheric lenses. After knifing the total power was slightly over 4W. With better mirror adjustment 4,1W should be possible. Mirror holders were pretty tricky to align an as I was very busy this day I wasnt able to stay there till all things were done, so the actual power remains the same or was increased a bit...I dont know.

I may be wrong but thats what I remember. Hope it helps

[lasertack]

@ ALL

Just to avoid confusion. The shipping fee to USA may differ, depending on total value, because of the insurance. I´ll try to ship every order by airmail, because it is much faster than sending it as package by DHL.
If somebody orders for a total of let me say 24€, the shipping fee will be 5€, shipping fee for an order with a value of 230€ will bee 10€. Thats just examples. So please dont think, that I try to fool somebody by charging different shipping fees.

Alex

[chad]

Those edges look pretty sharp. I am not worried about them at all. They look supper efficient too.

Nice little prism mirror!

Chad

[andy_con]

Don't think we really need the macro-shots for that... lookie a li'l closer..

Attachment 31431

..yes, the macro-shots will help show-up edge quality - which, yes, is important, but a different 'issue' vs a chamfered-edge (..as opposed-to a razor-sharp edge..) Still, looks-like even Kv uses at-least somewhat chamf'd prisms -

Attachment 31432

.. so, perhaps it will not prove to be that much of an issue.. in any case, we should-see some efficiency-gains over mirror-edging.. whether these will prove to be yet another 'game-changer', is TBD, but... at least these prices are making it 'reasonable' to-explore...

@ Alex - just-curious if you've actually built these into a multi-watt knifed-rig, and, if-so, what kind of efficiency did you see vs mirrs? Yes, it's understood that 'choice of lens, diode-current', etc, etc are all 'factors', but even so, it would be easy to say, set-up a rig with, say, 4x diodes, each putting out 1.2W of 445, post-lens, and off a 4-up knifed mirror-rig, you got "X", when-summed (..this also assumes that, yes, you are an ace at knifing.. ...And again, same test-conditions, only using these prisms, and you got "Y", when summed... something like that.. ..Any real-world 'case-study' data like that?

..Not trying to appear 'critical' or anything, but, ya know.. these are the sorts of questions potential-buyers of 50-60 pieces of practically-anything, tend to ask.. And, while this sort of 'minutia' may-not be too 'relevant' for those building 2-4- ..maybe even 6-bangers, for those doing 10+ up's... 'chamfered vs un-chamf'd' is at the very-least, something you wanna know, going-in..


cheers..
j

if soemone wants to send me some free blue and red samples ill gladly knock up some modules to do soem testing.

i wont go into full details but these would be easiler for knife edging, having the mirror mounts straight into the beam is always easier than having mirrors mounts at 45 degrees to the beam

[planters]

Chad,

They do look pretty sharp, but I would still worry. The current knife edge mirrors do literally look like knives, very sharp, to the naked eye. They nevertheless spill a fair amount of light and cause some ambiguity when trying to get a best position. If the rounding is a problem the round profile may be more amenable than a sharp edge to some delicate edge grinding to minimize it with out chipping, but this would be an additional hassle.

[chad]

For me the fact that they are *Exactly* the same dimensions and have a 'almost to the edge' good dicro coating is enough. The 90 makes it easier to machine things to hold them.

Remember that these things are tiny, so the rounded edges are going to be very small. Here is His closeup zoomed and straightened.



For my setup the benefits outweigh the drawbacks, I think

chad

[lasertack]

@ chad!

I agree, the edges are very sharp. The rounded edges should not effect the knifing negatively, because the rounded part is too small.

@planters

You wont find prisms (made by a high quality manufacturer) without rounded edges. The reason is very simple, it´s just to avoid breaking off the edges. It would be nearly impossible to handle them without any damage when the edges are sharpened like a scalpel.
Keep in mind, that these parts are very tiny and filigree and if it falls out of your hand, for whatever reason, the edges would break off.

[chad]

The other thing that you have to remember is they have to coat these somehow. That means they have to have something to hang on to. I am guesstimating a .063mm radius. Personally not enough for me to sweat.




chad

[lasertack]

@chad

Thank you for the pic. Very useful.

Alex

[planters]

I agree.
The scale is VERY small and I won't disagree with your estimate of the radius, it does appear at about that level. The upcoming micrographs, I suspect, will support something like this. At the risk of arguing against myself, I inspected a number of prisms this AM and the larger the glass the proportionally larger the radius of the chamfer. So, these very small optics may inherently be the better choice for tight edging even if the clearances with some collimators might dive you crazy.