The dynamic range, defined as the range of intensity ratios for which two writing beams can induce a detectable photorefractive grating, is measured for ferroelectric crystals BaTiO3, KNbO3, SrxBa1−xNbO6, BaxSr2−xK1−yNayNb5O15. Our results show a large dynamic range in all these crystals, 70–100 dB, which should prove these crystals useful for signal processing and computing applications. The observed limit on the dynamic range was due predominantly to the detector noise and therefore was not the fundamental limit imposed by the underlying physics of photorefractive noise. The calculations of noise based on limited photon density flux (shot noise) and thermally induced grating fluctuations (thermal noise) show the dynamic range to be 4–5 orders of magnitude higher than that observed experimentally.
© 1992 Optical Society of America
Original Manuscript: December 23, 1991
Revised Manuscript: May 20, 1992
Published: September 1, 1992
Tallis Y. Chang, John H. Hong, Frederick Vachss, and Robert McGraw, "Studies of the dynamic range of photorefractive gratings in ferroelectric crystals," J. Opt. Soc. Am. B 9, 1744-1751 (1992)