DLA Optimization Software

Contents

This matlab program is used to generate optimized dielectric laser accelerator structures.

The code produces two separate structures:

• optimized for maximum acceleration gradient
• optimized for maximum acceleration gradient divided by the maximum electric field amplitude (either in material or design region).

The optimization procedure is as follows:

1. Start with starting structure (empty space, uniform, or random can be chosen).
2. Repeat until convergence:
   • Use the adjoint variable method to get the change in objective function with repsect to each design pixel permittivity
   • Slightly perturb each pixel towards a higher objective function value simultaneously

Code allows for gradient ascent, RMS prop, gradient ascent with momentum, and Adam optimization algorithms.

Can be used to optimize free-space coupled structures, buried gratings, or waveguide coupled structures.

Paper information

This code was used in work related to this paper:

Method for Computationally Efficient Design of Dielectric Laser Accelerator Structures

For more details please read it!

How to run simulation

Just run the script "optimize.m". The FDFD code and sparse matrix LU-factoring code is located in "dependencies/". The entire directory needs to be added to the path to work correctly

Citing our work

If you would like to use this code, please cite the paper:

    @article{Hughes:17,
        author = {Tyler Hughes and Georgios Veronis and Kent P. Wootton and R. Joel England and Shanhui Fan},
        journal = {Opt. Express},
        keywords = {Gratings; Optical devices; Subwavelength structures},
        number = {13},
        pages = {15414--15427},
        publisher = {OSA},
        title = {Method for computationally efficient design of dielectric laser accelerator structures},
        volume = {25},
        month = {Jun},
        year = {2017},
        url = {http://www.opticsexpress.org/abstract.cfm?URI=oe-25-13-15414},
        doi = {10.1364/OE.25.015414},
    }