ellipsometer.md

(Yellow‑zone draft)

Ellipsometer#

Ellipsometers measure thin‑film properties using polarized light. Their operation is precise but inference‑heavy.

Dimensional Core (SET)#

• Spin: polarization
• Elec: detector response
• Temp: affects refractive index

Why Yellow‑Zone#

Ellipsometry relies on model‑dependent inference, not direct measurement. Substrate properties strongly influence results.

Regime Notes#

• pos‑regime: stable films, known materials
• Q‑regime: mixed layers, rough surfaces
• neg‑regime: unknown substrates, unstable films

Alignment Notes#

Needs clarity around model assumptions and substrate dependence.