Astronomers observe the chromosphere of the Sun with a filter that passes the red hydrogen spectral line of wavelength 656.3 nm. The filter consists of a transparent dielectric of thickness d held between two partially aluminized glass plates. The filter is held at a constant temperature.
a) Find the minimum value of d that produces the maximum transmission of this perpendicular H light (656.3 nm), if the dielectric has an index of refraction of 1.378.
b) What happens to the transmitted wavelength if the temperature of the filter is increased but the index of refraction does not change significantly?
c) The dielectric will also pass what near-visible wavelength? One of the glass plates is colored red to absorbed this light.