Tom,
Rowlands Ghosts are caused by period errors in making gratings. Instead
of getting s a single line there are beats (weak lines ) around the single linesall Gratings have these to some degree. If CD -roms are vary random then these
would smear to make broaden ed lines. If they are periodic enough they ne enogu
they will be seen is weak like lines around the expected ones.
Please excuse the typo's but our new system lacks an ediot that I
can use. )(progress??)
gary