Refractive indices at vacuum UV area (around 157nm)
Ohara
Measurement Service Center domestically first succeeded in developing a
method of precision refractive index measurement on optical materials
used in vacuum UV wavelength (around 157nm). Until today it was quite
difficult to obtain refractive index data at around 157nm. Ohara is
capable now to measure the refractive index at the wavelength to the 6
decimal places by the developed method. This new technology also enable
us to measure dispersion value at some particular wavelength and the
thermal coefficient of refractive indices under regular room
temperature (coefficient of refractive index variation by the change of
temperature in operation environment.)
For refractive index measurement in deep UV the shortest wavelength we
can measure is 185nm up to now with the conventional methods. In order
to measure at 157nm it is very necessary to remove almost all oxygen
from the entire measurement system because the light is damped by 1/70
per 1mm by oxygen in the air. Ohara challenged and succeeded in
overcoming the difficulty.
Please contact Ohara Corporation for further details.