Huray Surface Roughness

HuraySurfaceRoughness is a surface roughness model based on metallic spheres distributed over a matte surface.

This object corresponds to tidy3d.rf.HuraySurfaceRoughness (opens new window).

Relative Area

relative_area: Relative area of the matte base compared to a flat surface.

• Type: float number
• Constraint: greater than 0
• Default: 1

Coefficients

coeffs: List of $(f_i, r_i)$ values for the Huray model.

• Type: list of pairs
• Unit: $(\text{unitless}, \text{um})$
• Required field

f_i: Ratio of total sphere surface area to the flat surface area.

r_i: Radius of the sphere.

Roughness Correction

The power loss compared to a smooth surface is modeled as:

$\frac{A_\mathrm{matte}}{A_\mathrm{flat}} + \frac{3}{2}\sum_i \frac{f_i}{1+\frac{\delta}{r_i}+\frac{\delta^2}{2r_i^2}}$

where $\delta$ is skin depth, $r_i$ is the sphere radius, $A_\mathrm{matte}/A_\mathrm{flat}$ is the relative matte area, and $f_i = N_i4\pi r_i^2/A_\mathrm{flat}$ is the ratio of total sphere surface area to the flat surface area.