A programme of work was instigated to investigate and improve the efficiency, and
stability of intra-cavity étalons for the Argon ion laser, especially in the far blue to near
ultra-violet wavelength region, by using sol–gel prepared silica. The original program
has been modified by experiences outlined below.
We have attempted to differentiate between the sol–gel derived and the high temperature
prepared silica. We confirm that relatively small changes in thickness of silica monoliths
can give rise to proportionally much larger changes of refractive index. Our main target
has been to assess whether it is possible to make a new optical material that shows
insignificant changes in optical path length or refractive index with temperature. [Continues.]
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.