Enhanced method for determining the optical response of highly complex biological photonic structures

Abstract

We present a set of techniques that enhances a previously developed time domain simulation of wave propagation and allows the study of the optical response of a broad range of dielectric photonic structures. This method is particularly suitable for dealing with complex biological structures, especially due to the simple and intuitive way of defining the setup and the photonic structure to be simulated, which can be done via a digital image of the structure. The presented techniques include a direction filter that permits the decoupling of waves traveling simultaneously in different directions, a dynamic differential absorber to cancel the waves reflected at the edges of the simulation space, and a multifrequency excitation scheme. We also show how the simulation can be adapted to apply a near to far field method in order to evaluate the resulting wavefield outside the simulation domain. We validate these techniques, and, as an example, we apply the method to the complex structure of a microorganism called Diachea leucopoda, which exhibits a multicolor iridescent appearance.

Optical function of the finite-thickness corrugated pellicle of euglenoids

“…The PSM simulates the propagation of electromagnetic waves via an analogy with the propagation of transverse mechanical waves in a planar network of particles coupled by elastic springs [23,30]. The movement of the particles is constrained to the transverse direction (z), i.e., to the direction normal to the plane of the two-dimensional array, the x; y plane.…”

“…This approach can be applied to two-dimensional problems involving dielectric materials illuminated by TE-polarized light. Further details can be found in [23,30].…”

“…We also investigate the near field in the vicinity of the structure. To perform this calculation, we employ a photonic simulation method (PSM) especially suitable for dealing with complex biological structures [23].…”

Kirchhoff and Ohm in action: solving electric currents in continuous extended media

“…For example, the circulation of electric currents in water bodies, the human body or in soils [1][2][3], or in a continuum bi-dimensional or three-dimensional space. It is also of interest to know the response of resistive or reactive complex electric circuits, as in the case of modelling of nanophotonics, photonic structures [4,5] and metamaterials, by the application of a circuital model [6]. For that reason, it is useful to find a numerical simulation that easily allows evaluating the response of complex electric media.…”