Abstract
Colorimetrical studies on the interference color of crystal between Nicol prisms, when (i) the crystal is birefringent and an achromatic retardation is added thereto, (ii) crystal is active (crystal has the power of rotating the plane of polarization), and (iii) the birefringence of the crystal is a function of the wavelength, are given. It was found that in case of (ii), there exists extremely sensitive change of color with respect to the change of birefringence, called “hypersensitive color”. The fact that the loci of the interference color of the active crystal are ellipses, is also proved analytically.
