---
title: Live 8 × 8 µm y-dipole SiN/SiO2-slab atom-slot optimizer
---

# Live 8 × 8 µm y-dipole SiN/SiO2-slab atom-slot optimizer

**Worker:** not active · **stage:** `projected_q_over_v_continuation` ·
**status:** `running_fixed_beta_pure_q_continuation` · **checkpoint age:** 1512.0 min

This independent clean restart starts from a uniform density-0.5
SiN topology inside a planar SiO2 stack. The oxide occupies the complete x–y
simulation plane, including the x and y PML cells. An explicit immutable air
body cuts the full strip `-0.5 µm < x < 0.5 µm` through the oxide, SiN, and
complete transverse/PML extent. A centered y-oriented atom and symmetric
TE-like source select the Ey cavity family. Full
x/y/z symmetry retains one octant of the 8 ×
8 µm physical design.

Stage A uses raw Adam on the fixed absolute Q=10,000 ideal atom time trace.
Once temporal improvement clearly slows with a trustworthy Q≥100, Stage B
switches to adaptive-trust L-BFGS-B on pure same-pole harmonic Q using only
the raw 50 nm SiN pixels. The next diminishing-return handoff unlocks SiN and
per-side SiO2 thickness while preserving `t_SiN + 2t_SiO2 ≤ 1.000 µm`.
Gradual fixed-beta continuation and then topology-free smooth cubic-spline
boundary optimization follow under the same pure-Q scalar. Q/V, atom-local
volume, Purcell, fields, pole continuity, and trust health remain live
telemetry.

The separate 12 × 4 µm first-step air-strip-width sweeps compare independent
density-0.5 temporal seeds from 1.0 to 2.0 µm for
{doc}`100 nm SiN <atom_strip_seed_width_sweep_dashboard>` and
{doc}`300 nm SiN <atom_strip_seed_width_sweep_sin300_dashboard>` without
altering this archived campaign.



| quantity | current |
|---|---:|
| temporal Adam updates | 197 · plateau not detected (16/20 trend samples) |
| pure-Q substage / accepted since temporal handoff | joint_stack / 55 |
| pole accepted updates / trials | 825 / 6702 |
| Q | **4011.8** |
| best recorded Q (trust gate shown above) | 4153.47 |
| field / energy Q | 4305.52 / 4011.8 |
| Q-estimator ratio | 1.07321 |
| pole wavelength | 834.441 nm |
| source-center wavelength | 827.606 nm |
| field-monitor wavelength | **834.383 nm** |
| design-region slab thickness | **0.427735 µm** |
| Stage-B thickness coordinate / range | **True** / 0.050–0.500 µm |
| SiO2 thickness per side | **0.215482 µm** |
| Stage-B SiO2 coordinate / maximum | **True** / 0.475 µm |
| stack-thickness constraint | t_SiN + 2t_SiO2 ≤ 1.000 µm |
| SiO2 x–y extent | **complete simulation plane, including x/y PML** |
| air-strip cutout extent | **complete y/z simulation span, including PML** |
| physical mode volume | 35.2435 µm³ |
| normalized mode volume | 60.6586 (λ_pole/n_air)³ |
| Q / normalized atom volume | **68.473** |
| Purcell from Q/V | 5.20332 |
| fitted atom-pole amplitude at source clear | **0.000565168** |
| absolute atom-trace peak / handoff | 0.234464 |
| source spectral power at pole / actual carrier | 0.961621 |
| reciprocal guided-Purcell proxy | **7.04699e-08** |
| guided-Purcell proxy / handoff | **0.5224** |
| Stage-B volume treatment | **none — pure log harmonic Q is optimized** |
| three-window V span | 0.0578487 |
| active Q/V run time / window | 2.65 / 0.8 ps |
| gradient backend / storage | **`checkpointed`** / 212 lean checkpoints |
| structural backend decision | `exact nondispersive PML tape exceeds the automatic memory budget` |
| exact reversible PML tape size | 10.9784 GB |
| frozen measured value+gradient speedup | —x |
| Q/V fit start / nominal lifetime per window | 0.25 ps / 0.125 τ_amplitude |
| precision-triggered tape growths | 4 |
| final ringdown field-power / energy fraction | 0.430423 / 0.40645 |
| finite-step adjoint direction verified | **True** |
| ideal temporal fidelity | 0.493914 |
| active objective / value | **pure log harmonic Q** / 8.3317 |
| stage plateau / reason | **False** / `collecting_two_optimizer_memories` |
| plateau samples / evidence window | 16 / 20 |
| objective slope / detectable slope | — / — |
| trust-floor restarts since progress | 0 / 2 |
| practical fixed-beta Q/V gain over one memory | 0.0592407% / 1% limit |
| practical plateau samples / required | 11 / 11 |
| practical trust radius still expanding | True |
| healthy / cumulatively pruned curvature pairs | **1 / 544** |
| L-BFGS / current-gradient predicted-ascent ratio | **0.135332** |
| replay-triggered curvature recoveries | 72 |
| maximum last density motion | 0.0262905 |
| trust radius | 0.00376506 |
| binarity score (1 is binary) | **0.984335** |
| trainable gray fraction (0.05<rho<0.95) | **2.12515%** |
| archived tangent-stage Q/V floor | 43.2415 |
| projection beta / eta | **15 / 0.5** |
| fixed-beta accepted Q/V updates / transition | 16 / objective plateau |
| material parameterization | `unfiltered_centered_tanh_projected_50nm_pixels` |
| hard atom access | **1.000 µm full-y air strip, immutable** |
| pixel / grid | 50 nm / [101, 95, 35] |
| non-PML z span / material-stack-to-PML air gap | 2.50 / 0.82 µm |
| z PML | 0.50 µm per side |
| z-padding convergence audit | `not_run` |
| 1.50→3.40 µm replay: residual / field-Q / energy-Q change | nan% / nan% / nan% |
| binarization / material projection / filter | **True / True / off** |
| physical waveguide escape eta | not part of the active objective |

## Q, V, objective, and optimizer history

![Q, V, objective, and motion](../_static/generated/atom_strip_cladded_tm_q_history.png)

The Q axis is linear. A pole is not trusted until the centered
Ey and total
energy decay estimates agree. Mode volume uses the geometric mean of their
three same-pole windows and the
same fitted pole wavelength; the local permittivity is exactly air by the hard
geometry constraint. This run imports no geometry, pole state, or optimizer memory from earlier campaigns.





## Ideal and measured atom response

![Ideal and measured temporal response](../_static/generated/atom_strip_cladded_tm_q_response.png)

The target has fixed amplitude and phase for Q=10,000, beta one, V=0.1 µm³,
and perfect Ey-polarized overlap. It is not rescaled
to fit the simulation.

## Geometry and fields

![Initial, current, and difference geometry](../_static/generated/atom_strip_cladded_tm_q_geometry.png)

![Ey field profiles](../_static/generated/atom_strip_cladded_tm_q_fields.png)

## Downloadable layout

**Layout status:** provisional density-0.5-contour GDS preview. The ZIP includes the GDS, JSON stack/metric
manifest, and README. Before the spline handoff the GDS is intentionally marked
as a thresholded preview; after handoff it is the fabrication-oriented smooth
boundary representation. GDS is planar, so use the manifest for SiN and SiO2 thicknesses.

{download}`GDS bundle <../_static/downloads/atom_strip_cladded_tm_q/atom_strip_cladded_tm_q_gds_bundle.zip>`

{download}`Current GDS <../_static/downloads/atom_strip_cladded_tm_q/atom_strip_cladded_tm_q_current.gds>`

{download}`Layout manifest <../_static/downloads/atom_strip_cladded_tm_q/atom_strip_cladded_tm_q_manifest.json>`


{download}`Exact campaign methodology <../_static/downloads/atom_hole/METHOD_XYZ_Y_STRIP_SIO2_SLAB_8X8_YEE.md>`