Knowledge Bank

Oriented films of the trigonal alkali metal nitrates, which behave effectively as single crystals, can be grown in optical contact with silicon and Irtran 6 atr elements from the corresponding pure melts. Contrary to earlier $thoughts,1$ spectra from such crystals are not strongly influenced by crystal distortion at the interface. Rather the unusual experimental curves, typified by a nearly complete lack of TE and TM band overlap for the $\nu 1$ mode of $NaNO3$ (II), have been found to be predictable using optical parameters generated from a damped oscillator model. Substitution of the empirically calibrated optical constants into Fresnel’s equations for the case in point (unique crystal axis perpendicular to the sample-element interface) yields nearly quantitative agreement with the experimental curves.