Knife-edging - flex mounts at 90 or 45 degrees?

[taggalucci]

I'm planning an octo-combiner and have seen examples of knife-edging where:

• the flex mounts are perpendicular to the diode mount and the mirror glued to the 45 degree edge of the flex mount e.g. Edison
• the flex mounts are at 45 degrees to the diode mount and the mirror glued to the front edge of the flex mount e.g. Arctos

I can see that there are a benefits in both, but I'm just wondering if there's a reason one might choose one approach over another and what your thoughts and recommendations are.

[planters]

For what it is worth, I would arrange the mounts at 90 degrees. Firstly, there is a little less calculating involved in drilling the base plate and secondly, if you do move to prisms then the larger area of the front of the flex makes gluing a little more precise.

[taggalucci]

Great, thanks

It seems I'll be fine with the 2 axes of adjustment. I'll just need to glue my mirrors on precisely - I'm thinking of making a jig for this.

[planters]

I'm thinking of making a jig for this.

I strongly recommend using a jig. Depending on the source of your mirrors, this saves time and is not stressful, but if the edges of the mirrors are not well made then you may not be able to take advantage of this. You do have a third axis of adjustment with the base slot. Cap head screws with washers tightened slightly will allow you to wiggle/slide these mounts in and out by a surprisingly fine amount on the order of tens of microns.

[taggalucci]

Thankfully these mirrors' edges are well made. I got these some time ago from a group buy.

I understand the 2 axes of motion I'll have in the horizontal plane (1 longitudinal for the mirror mount and 1 lateral for the diode mount), but not a 3rd as you suggest. Please could you illustrate this further?

[planters]

I see the confusion. The three axes I was describing were the two for tip and tilt within the flex mount and one for in/out translation of the flexmount itself.

Because the translation of the mount will allow you to adjust each of the mirrors to just clip its diode's beam and add it to the growing stack, I would mount the diode base plate flange so that the diode can slide laterally to just intercept the mirror right at the edge. Keep the diode beams strictly at right angles and avoid the temptation to aim the diode output to the edge of the mirror with turning/rotation as this will mess up the stack position later. The 445's vertical stripe is about 1mm thick, so if adding more than a few it's a good idea to drill each flex mount-mounting hole in the base plate 1mm further out as you move down the line. This leaves you with each screw nominally in the center of the slot and maximizes your available adjustment range.

[taggalucci]

Great Thanks for clarifying.

I've taken what you've described on board. I believe I have this covered in my current conceptual design detailed in the following thread...

http://www.photonlexicon.com/forums/...63133DG-Diodes

[dnar]

I found it best to mount the flex mounts perp to the diode with the mirrors glued to the 45. Better simply because of the adjustment.