Abstract

Holographic data storage systems typically utilize angular,¹ wavelength,² or phase- coded multiplexing.³ Of these, the first two techniques exploit the dependence of the Bragg condition on the angle and wavelength of the writing beams. However, the index of refraction is an additional degree of freedom in the Bragg condition that can be controlled by an external electric field. In the case of counter-propagating signal and reference beams, both normally incident on the crystal, the Bragg condition reduces to 2Λ_g = λ/n. By differentiating the Bragg condition, we obtain a simple relation for small deviations Δn, Δλ, ΔΛ_g from the nominal values n, λ, Λ_g that illustrates the equivalence between wavelength and electric field multiplexing:

© 1993 Optical Society of America