The ratio of the radiant absorption <i>A</i> to the transmittance <i>T</i> of a weakly absorpting lamina is expressed in terms of its extinction coefficient <i>k</i>, index <i>n</i>, and thickness.
© 1978 Optical Society of America
Philip Baumeister and David Smith, "The absorption of a weakly absorbing thin layer," J. Opt. Soc. Am. 68, 1284-1284 (1978)