Just some pix I already have up on the server: These are an Alpha 8045 heatsink. The first pic is the factory surface under an optic flat. It had a lot of machining marks and was not a flat and/or polished enough surface to show any interference fringes.
The second pic is after lapping and several polishing steps down to 1 micron diamond.
The third pic is this polished surface under the optic flat. You can see the interference fringes (rings). As BillA stated, these rings are very hard to take photos of. You can see that most of the center area of the heatsink is within one ring and the rings get closer together toward the edge (the edges are rounded off, although to a 'very' slight amount.) Getting a large surface like this to minimal rings is hard to do (tooting my own horn.)
