We improved the control software of the laser polishing system: now the rotation speed is large when the laser is missing the disk because of the flats.
We used S1600479 as a test. This substrate was marked as damaged and had a clear chip. It went thoruhg two different polishing runs
The second run was probably too slow, and we can see some kind of traces left on the main surface close to the edges
We then laser polished a good subtrate (S1600439) which was already measured before (137) and after annealing (144), with good Q values. This is a substrate from the first batch we received from Mark Optics. The polishing was done at ~ 18W and 0.5 mm/s.
Some pictures below: