Dataset for "Surface-enhanced Raman Spectroscopy Facilitates the Detection of Microplastics < 1 μm in the Environment"

Data collection method:

Finite difference time domain (FDTD) simulations were performed in Lumerical (a commercially available photonic simulation software) to gain insight into the electric-field distribution within the inverted pyramidal pits of the Klarite substrates. The material properties of the Au Klarite substrate was emulated using a Johnson & Christy model for Gold. Nine pyramidal pits were generated in the design modeller in a 3 x 3 grid with dimensional equality to the experimental Klarite. The Eulerian mesh was a cuboid FDTD simulation domain enclosing the central pit (a single unit cell). The granularity of the mesh was 8.5 nm and was selected based on a mesh sensitivity study to determine convergence and quality of results (see Supplemental section). In the cartesian basis, the z direction is normal to the surface of the Klarite; the x and y directions coincide with the plane of the Klarite surface. Periodic boundary conditions were applied in the x and y directions; simulating an infinite array of pyramidal pits. A perfectly matched layer (PML) boundary condition was applied to the upper and lower boundaries of the domain to model an open boundary. A linearly polarised plane wave pulse of light was incident directly onto the Klarite from 0.7 µm above the surface. The spectrum of the pulse was nominally centred at 785 nm to match the experimental laser wavelength of this study and had a bandwidth of 500 nm; the amplitude of the pulse was E_0= 0.5 V/m. A planar electric field monitor was placed in the vertical cross-section of the inverted pyramid pit, perpendicular to the direction of polarisation to extract the plasmonic electric field distribution at the wavelength of the incident light. The simulations were repeated for two other wavelengths of incident light (685 nm and 885 nm) to determine the wavelength dependence of the electric field distribution.

Technical details and requirements:

They were published in python using matplotlib

Additional information:

Text file data exported from lumerical