A 3D finite element mathematical model has been developed for representing a behavior of a magnetic mirror and nano antenna subject to polarized incident light. This model represents the fourth generation of magnetic mirror with the goal of suppressing the diffraction.
The goal is to apply nanotechnology to create new devices to enhance both the imaging and detection of light. The capability to fabricate the nanowire devices has been demonstrated to create artificial molecules that allow interaction with the magnetic portion of an electromagnetic wave. Fabrication of these nano antennas can be utilized to enhance detection of light as well as to make proof-of-concept devices. The imaging and detection technologies are broadly applicable to astrophysics, planetary, and Earth sciences.
The finite element model represents a 3D nanowire or nano antenna cell structure with similar physical geometry to what has been fabricated earlier. The model consists of a sinusoidal aluminum nanowire that is etched on the top of a silicon substrate and backed by aluminum slab. The full size of this geometry is around 440×440 nanometers. This structure is bounded on four sides by period boundary conditions representing similar structures on each side. The cell structure is illuminated by a polarized light from the top surface and exited from the bottom surface. The presence of optical oscillators at certain frequencies over the structure creates a plasmonic effect that creates evanescent light at the surface of the nanowire.
The finite element formulation of the nanowires for magnetic mirrors and nano antennas allows the project to optimize and enhance the nano-fabrication process before the costly fabrication process. The geometrical model representing the physical structures can be varied in size, dimension, material property, and incident beam polarization, simulating the magnetic behavior and customizing these properties to better optimize a working magnetic mirror device. These simulations are considerably cheaper and faster than the fabrication process. For instance, the 3D visualization of the field distribution in the structure cell and reflectivity coefficient could provide invaluable knowledge of the shape of the nanowires and optimal wavelength.
This work was done by Shahram Shiri and John Hagopian of Goddard Space Flight Center. GSC-16424-1