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Campaign: quan_loncar_meep_lab/device23_surrogate_freeform_q

Assembled 2026-09-05 15:02 UTC.

Engine: quan_loncar_meep_lab · path: engines/quan_loncar_meep_lab/campaigns/device23_surrogate_freeform_q/

README

Device23 continuous free-form surrogate-Q campaign

This is the arbitrary-boundary counterpart of the successful parameterized design23_pure_bfgs_maxQ experiment. It climbs only the selected-fidelity FEM log(Q) surrogate over all hole and waveguide-sidewall boundaries. Tidy3D runs every ten accepted steps as a diagnostic and never steers the optimizer.

Fixed policy

  • Device: FDTD-qualified Device23 40-hole seed.
  • Boundary variables: every sample of all 40 hole contours and of the outer sidewall. The lower wall follows by mirror symmetry.
  • Sidewall scope: free for |x| <= 4.5 µm, cosine-tapered to zero motion, and pinned for |x| >= 4.9 µm to retain uniform leads.
  • Sidewall range: the stored half-domain reaches y = 0.60 µm, about 322 nm beyond the initial wall.
  • Objective: nominal tracked-pole log(Q) only.
  • Optimizer: projection-free pure log(Q) shape-gradient ascent with calibrated adaptive normal displacement; not BFGS.
  • Mode continuation: restart from the accepted complex pole and follow each trial's first-order predicted pole within 0.005 / µm; fail closed if absent.
  • Trial transform: Hamilton–Jacobi advection only. No smoothing, reinitialization, pruning, or curvature flow occurs inside the line search.
  • Persistent reference: trusted accepted step 2 is meshed deterministically and frozen. Every incumbent and candidate is an absolute ALE deformation of that reference connectivity. Restarted incumbents must reproduce their recorded Q to 1e-5 in log(Q).
  • Acceptance: positive tracked-pole log(Q) gain on the persistent reference connectivity. Remeshing is excluded from local acceptance. Boundary-transfer, element-measure, feature, localization, residual, and pole-continuation gates fail closed.
  • Safeguards: 70 nm minimum feature, localization ≥0.55, residual below 1e-8, bounded deformation transfer, and per-element measure limits.
  • FDTD: fixed 16 ps diagnostic ringdown, automesh at 14 steps/wavelength, no override regions, every 10 accepted steps.
  • Cloud cap: 5 FlexCredits in fdtd_budget.json.
  • Stop: touch runs/20260812T131106Z_device23_surrogate_freeform_q/STOP.

Live dashboard

https://www.christianmlange.com/cavitygrad/hub/runs/20260812T131106Z_device23_surrogate_freeform_q/dashboard/

Launch

./engines/quan_loncar_meep_lab/campaigns/device23_surrogate_freeform_q/launch_service.sh

The process resumes from the newest checkpoints/field_step_NNNNNN.npz and runs until explicitly stopped. The service is cavitygrad-device23-surrogate-q.service.