# Frozen 150 nm SiN Fourier-to-pixel atom-hole campaign

This page preserves the terminal checkpoint selected by the user after the
trajectory visibly saturated. It is not overwritten by the successor 200 nm
campaign.

## Executed configuration

| Quantity | Value |
|---|---:|
| Material stack | 150 nm Si3N4 slab in SiO2 |
| Atom | z-oriented, 780.24 nm |
| Immutable opening | 1.0 µm-diameter through-slab air hole |
| Trainable region | 9.6 µm-diameter extruded 2-D mask |
| Grid | 25 nm; slab resolved by 6 cells |
| Symmetry | x/y/z, 8× reduced solve |
| Parameters | 40,000 Fourier coefficients → 40,000 pixels |
| Terminal update | 1283 |
| Fourier-to-pixel handoff | update 991; executed-density RMSE 0.0 |
| Initial / best LDOS | 0.537764 / **0.682342** |
| Best literal-binary LDOS | **0.682342** |

The fixed-frequency matched-vacuum LDOS improved by 26.9%. The result remains
below vacuum and no trustworthy resonant pole emerged. Forty-seven independent
pulsed audits were attempted; none passed all field/energy agreement and
window-stability gates. The largest fitted candidate Q was 42.53. At the final
checkpoint, field- and energy-decay fits gave Q=38.61 and 172.65 respectively,
so the conservative Q was not accepted and shifted optimization correctly
remained disabled.

## Geometry and material stack

```{figure} ../_static/generated/fourier_atom_hole_sin150_final_geometry.png
:alt: Initial and terminal 150 nm Fourier-to-pixel geometry with xz material sections

The literal initial and terminal masks and the executed 150 nm xz stack.
```

## Complete optimization and Q-surveillance history

```{figure} ../_static/generated/fourier_atom_hole_sin150_final_progress.png
:alt: LDOS, continuation, gradient, and rejected Q histories for the 150 nm campaign

Fourier and pixel stages share one update axis. Candidate pole fits remain
visibly separate from trusted fits; no candidate crossed the fail-closed gate.
```

## Terminal spatial spectrum

```{figure} ../_static/generated/fourier_atom_hole_sin150_final_spectrum.png
:alt: Spatial spectrum of the terminal 150 nm pixel controls

At the terminal pixel stage this is the diagnostic Fourier transform of the
pixel controls, not a claim that Fourier coefficients remain active controls.
```

## Terminal electric field

```{figure} ../_static/generated/fourier_atom_hole_sin150_final_field.png
:alt: Terminal Ez field in xy and xz cross-sections

Paired atom-frequency xy and xz phasors from the same executed checkpoint.
```

The full resumable artifact is retained locally as
`benchmarks/artifacts/invdes_fourier_atom_hole_ldos_sin150_isotropic_v3.npz`.