Compensation of fabry-perot surface defects. 2: silicon oxide compensating layers

The properties of a Fabry-Perot etalon, with surface defects compensated by irradiating a silicon oxide film, are computed for the case in which the initial surface defects function is rectangular. As a result of absorption, the compensating layer of silicon oxide must be deposited before the reflecting coating if the etalon is to be used at uv wavelengths. For visible wavelengths, the compensating layer may be a half-wave silicon oxide film deposited over the reflecting coating. An example is discussed in which the rms deviation from the mean thickness of an etalon is reduced from 2.37 nm to 0.80 nm. An automatic self-compensating process is proposed in which the radiation transmitted by an etalon may be used to produce an appropriate change in the thickness profile of a silicon oxide film.