Design23 · pure analytical BFGS

Pure BFGS (no max-Δnm trust cap) on analytical Q + ∇Q · FDTD every 3 steps is diagnostic only (never accept/reject) · cap 10 FC · — · —

Quality factor progress

Analytical Q (BFGS) FDTD diagnostic Q
Q vs accepted optimization step (log scale). FDTD points do not alter the optimizer path.

FDTD |E|² midplanes (Tidy3D plot_field + geometry)

Waiting for FDTD field data…
|E|² XY midplane — initial FDTD
XY midplane · initial FDTD
|E|² XZ midplane — initial FDTD
XZ midplane · initial FDTD
|E|² XY midplane — latest FDTD
XY midplane · latest diagnostic FDTD
|E|² XZ midplane — latest FDTD
XZ midplane · latest diagnostic FDTD

Design parameters vs seed (current − initial)

Gap Δ (nm) Mean radius Δ (nm) · ½(Δrx+Δry) Ellipticity Δ (nm) · Δ|rx−ry|
Hole index 0 = center-most pair. Values are current geometry minus seed.

Accepted analytical steps (tail)

#Qλ (nm)Δmax nmα
Δmax is the accepted BFGS step’s max |Δcoordinate| (no trust cap). α is Armijo line-search scale.

FDTD diagnostics (no gating)

StepFDTD QVeff/(λ/n)3Pred QFC
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