If an elementary hologram with grating vector K is recorded in a photosensitive material, the complex refractive index is modulated with the same spatial frequency K. A beam-coupling measurement is a proper tool for simultaneous investigation of the absorption grating and the refractive-index grating, which correspond to the imaginary and the real parts of the complex refractive-index modulation, respectively. Using beam-coupling analysis makes it possible to determine the magnitude of the refractive index and the absorption grating as well as their phase shift with respect to the writing intensity pattern, with one single-beam-coupling measurement. The theoretical foundation of beam-coupling analysis is given. A few numerical examples point out the main characteristic of beam-coupling analysis.
© 1993 Optical Society of America
Original Manuscript: April 13, 1992
Revised Manuscript: January 4, 1993
Manuscript Accepted: January 13, 1993
Published: July 1, 1993
F. Kahmann, "Separate and simultaneous investigation of absorption gratings and refractive-index gratings by beam-coupling analysis," J. Opt. Soc. Am. A 10, 1562-1569 (1993)