Octave Toolbox for Computer-Generated Holograms (CGH)

Ulf GRIESMANN, 2020

A toolbox for Octave to compute the layouts of computer-generated holograms from scalar phase functions describing the optical action of holograms in optical imaging systems. The optical function of a hologram is generally modeled with optical ray-tracing software and it can be encapsulated by a scalar optical phase function $\phi$(x,y). The toolbox converts phase functions into equivalent binary or multi-level holograms. The algorithm used in this toolbox takes advantage of the relationship between the local derivatives of phase functions and the local geometry (curvature) of isophase lines. The isophase-following algorithm is easily extended to phase functions with singularities and discontinuities that occur in some optical applications. A full description of the toolbox algorithms has been published.. The GDSII Toolbox can be used to create hologram layouts suitable for fabrication with direct-write lithography systems. The CGH toolbox also includes a family of functions for the robust and efficient estimation and evaluation of Zernike polynomials, which are widely used in optical applications.

Copyright

The functions in this toolbox are in the Public Domain. For details see the file LICENSE in the root directory of the toolbox.

Documentation

Additional documentation is available on:

https://sites.google.com/site/ulfgri/numerical/cgh-toolbox

in a user manual that describes the installation of the toolbox and its use through a set of detailed examples.

Software Dependencies

The CGH toolbox makes use of the Octave Parallel Package to speed up the computation of holograms on computers with multiple CPU cores. The Parallel Package can now be used on all common operating systems. In addition, the CGH toolbox requires the Octave Optimization Package. Symbolic computations of Zernike polynomials require the Octave Symbolic Package and an installation of Python with SymPy.

Compiling

The CGH toolbox contains several MEX functions that must be compiled with a C compiler before the toolbox can be used.

For Octave on Linux, the mex functions are compiled by executing

$ ./makemex-octave

at the shell prompt. In Octave on Windows the mex functions are compiled by changing to the ./cgh-toolbox directory and running

makemex

at the Octave command prompt.

Help

If you find a bug in the software, please send a message to ulf.griesmann@nist.gov or ulfgri@gmail.com and I will try to correct it.