ldos-opt · Shaker et al. reproduction

3D SiN slab-gap

Octant Yee Maxwell, z-dipole, 1 μm vacuum gap, Si₃N₄ slab of thickness 0.15/0.78 λ₀ (the 3/7.8 run asymptoted at LDOS/vac ≈ 1.54). 2.5D extruded design, A-a35 erosion/dilation, hard-tied crystal when the octant has room.

Status

running

3d-free · shifted β=∞

LDOS / vacuum

3.19

seed 1.76 · best 3.47

best 43.4

Unknowns

120064

factor 166s · 8087 MB

Seed LDOS/vac=1.760. Starting unshifted.

Live dashboard → · run archive

3D permittivity — ε, xy midplane and xz at y=0 (mirrored to the full device)

Geometry

λ₀ = 1 μm (same as the 2D slot). Full gap 1 μm, so |x| < 0.5.
Nitride thickness 0.15/0.78 λ₀ ≈ 0.192 λ₀ (150 nm if λ₀ = 780 nm), snapped to an integer number of Yee cells. Extra air pad because the thin-film TM₀ mode is weakly confined.
Octant x,y,z ≥ 0: PMC at x=0, PMC at y=0, PEC at z=0. Outer PEC behind the PML.
Design is an in-plane density extruded through the slab (fabricable).
A-a35 fab: R=0.1λ, λ=3, Δη=0.25, gray weight 1, β_morph=8, period a=0.35.

See the 2D comparison for why these constraints.