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Manuscript Title: Dynamical holographic storage in photorefractive crystals.
Authors: J. Otten, A. Bledowski, K.H. Ringhofer, R.A. Rupp
Program title: DYNHOLO
Catalogue identifier: ACGA_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 69(1992)187
Programming language: Fortran.
Computer: IBM 3090-15S.
Operating system: CMS, DOS.
RAM: 5000K words
Word size: 32
Keywords: Optics.
Classification: 18.

Nature of problem:
A theory for dynamic holographic processes in photorefractive crystals in transmission geometry is presented as well as a numeric solution of the problem by the simulation program "DYNHOLO". With DYNHOLO we can solve holographic wave mixing problems with an arbitrary number of incident plane waves and with the intensity modulation depth up to unity.

Solution method:
A computer simulation program for dynamic holographic processes in photorefractive crystals for transmission geometry is presented. The change of light distribution over the interaction length are taken into account by dividing the crystal into a number of slices. The time development of the hologram in each slice is described by a series of following "reading" and "writing" steps:

* reading step (light transmission with fixed refractive index distribution): we solve the wave equation for a medium with a periodic refractive index distribution.

* writing step (change of refractive index distribution with fixed illumination): we use the charge transport model of Kukhtarev et al., taking into account as many Fourier components as necessary to solve the problem to a given accuracy for a given intensity modulation.


Restrictions:
We take into account only transmission geometry and neglect optical activity and absorption gratings. The incident beams should have equal polarization. All functions are assumed to be spatially periodic with the same period Lambda.

Running time:
Depends heavily on the input parameters, especially on the intensity modulation. For small modulation the solution is obtained within a few minutes, but for a modulation of unity an hour or more may be necessary.