Handbook of Optical Design, 3rd Edition

Appendix 3: Optical Materials

A3.1  OPTICAL GLASSES

Optical glass is mainly determined by the value of two constants, namely, the refractive index and the Abbe constant. A diagram of the Abbe number V_d versus the refractive index n_d for Schott glasses is shown in Figure A3.1. Besides the refractive index for the d line, several other quantities define the main refractive characteristics of the glass. The difference (n_F – n_C) is called the principal dispersion. The Abbe value expresses the way in which the refractive index changes with wavelength. The Abbe value V_d for the d line is defined as

$V_{\text{d}}=\frac{n_{\text{d}}-1}{n_{\text{F}}-n_{\text{C}}}.$

(A3.1)

There are many types of glass, but a common broad classification is as follows:

a.  Crown glasses are those with a relatively ...