A simple method of calculating the reflectance R, absorptance from the substrate, absorptance from arbitrarily distributed losses in the coating material or interfaces, and the phase distortion resulting from small wavelength changes, from heating, and from deviations in the thicknesses and indices of all or any one or more of the layers is given for normal-incidence multilayer-dielectric reflectors with 1 − <i>R</i> ≪ 1. The method is employed to derive useful expressions for absorptance, reflectance, and phase distortion that are not easily obtained by other methods. The key is the use of the simple zeroth-order (<i>R</i> = 1) electric field distribution in the coating (sinusoidal standing wave whose amplitude is reduced by a factor <i>n</i><sub>0</sub>/<i>n</i><sub><i>H</i></sub> at the coating surface and by a factor of <i>n</i><sub><i>L</i></sub>/<i>n</i><sub><i>H</i></sub> at every <i>LH</i> interface, and is unchanged at every <i>HL</i> interface) to obtain first-order results.
© 1977 Optical Society of America
M. Sparks, "A simple method for calculating the optical properties of multilayer-dielectric reflectors," J. Opt. Soc. Am. 67, 1590-1594 (1977)