This may be done by using the mechanical lapping and polishing system described above with a chemical such as silica or Cerium oxide, to remove about 0.01-0.02 micrometers of quartz, followed up with a wet etch in ammonium bifluoride to remove about 0.005 micrometers of quartz from the quartz substrate 2, resulting in a structure as shown in FIG. 2F. This additional step may help ensure a polished