basic

In this example we define a dimer of nanorods, model its optical response to linearly polarised light at fixed incidence, and orientation-averaged optical activity.

library(cda)
library(rgl)
library(ggplot2)
library(reshape2)
library(plyr)

Manually defining a cluster

# dielectric function
wvl <- seq(400, 900)
gold <- epsAu(wvl)

# define a cluster of particles
cl <- list(r = rbind(c(0, 0, 0),
                      c(0, 0, -100)),
            angles = rbind(c(0, 0, 0),
                           c(pi/4, 0, 0)),
            sizes = rbind(c(30, 10, 10),
                          c(30, 10, 10)))

# visualise
rgl.ellipsoids(cl$r, cl$sizes, cl$angles, col="gold")
rgl.viewpoint( theta = 0, phi = 20, fov = 70, zoom = 1)

calculate extinction, absorption, scattering of linearly polarised light at fixed incidence

# calculate extinction spectrum at fixed incidence

linear <- dispersion_spectrum(cl, gold)
ggplot(linear, aes(wavelength, value, linetype=type)) +
  facet_wrap(~polarisation) + geom_path()

calculate orientation-averaged optical activity

circular <- circular_dichroism_spectrum(cl, gold)

ggplot(circular, aes(wavelength, value, color=variable)) + 
  facet_grid(type~., scales="free") + geom_line()