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Sandbox Physics

Optics 086 · Waveguides, structured light, and modern optics

Microring & Whispering-Gallery Resonator

An independently initialized three-dimensional apparatus connects Whispering-gallery circulation, Critical coupling, Refractive-index sensing. Two dimensional physical controls, direct probe dragging, a detector trace, and three quantitative checks are recalculated from the stated equation.

Interactive modelMicroring & Whispering-Gallery Resonator
Primary prediction P1\mathcal P_10.500.50
Physical scale P2\mathcal P_250%50\%
Limit check V\mathcal V0.00π0.00\pi
Model regimevalid model regime\text{valid model regime}

Physics tutorial

How to investigate Microring & Whispering-Gallery Resonator

BackgroundMicroring & Whispering-Gallery Resonator is one independently initialized apparatus with three linked investigations: Whispering-gallery circulation, Critical coupling, Refractive-index sensing. Its two controls—Coupling amplitude and Detuning phase—feed the governing relation mλ=2πneffRm\lambda=2\pi n_{\mathrm{eff}}R. The page uses the stated modal, coupled-mode, effective-medium, or envelope approximation and marks its breakdown instead of presenting it as a full-wave result.

Why it mattersHow do ring size, loss, and bus coupling create a sharp resonance dip and circulating field?

Start with the essentials

Focus question
How do ring size, loss, and bus coupling create a sharp resonance dip and circulating field?
One-sentence intuition
The detector curve and all three numerical readouts are recomputed from mλ=2πneffRm\lambda=2\pi n_{\mathrm{eff}}R. Geometry and glow are presentation encodings; the equation, units, conservation or limit check, and validity indicator are the quantitative evidence.

Core mathematical model

Governing relation

mλ=2πneffRm\lambda=2\pi n_{\mathrm{eff}}R

The implementation evaluates this relation with dimensional inputs and an executable analytic or numerical benchmark. The page uses the stated modal, coupled-mode, effective-medium, or envelope approximation and marks its breakdown instead of presenting it as a full-wave result.

Common difficulties

Mistaking glow for measured power

Typical misconceptionA brighter cinematic trail must represent proportionally more optical power.

Better mental modelUse the detector and normalized readouts for comparison. Glow is deliberately nonlinear so weak structure stays visible.

Run the experiment

  1. 01

    Scene 1: Whispering-gallery circulation

    Select Whispering-gallery circulation. Sweep Coupling amplitude, hold Detuning phase fixed, and then reverse the roles. Drag the stage probe to repeat the first sweep directly.

    What to observe: Read the primary prediction, physical scale, limit check, and validity indicator together. Record where the approximation boundary changes.
  2. 02

    Scene 2: Critical coupling

    Select Critical coupling. Sweep Coupling amplitude, hold Detuning phase fixed, and then reverse the roles. Drag the stage probe to repeat the first sweep directly.

    What to observe: Read the primary prediction, physical scale, limit check, and validity indicator together. Record where the approximation boundary changes.
  3. 03

    Scene 3: Refractive-index sensing

    Select Refractive-index sensing. Sweep Coupling amplitude, hold Detuning phase fixed, and then reverse the roles. Drag the stage probe to repeat the first sweep directly.

    What to observe: Read the primary prediction, physical scale, limit check, and validity indicator together. Record where the approximation boundary changes.