Low-Coherence Interferometry (2D): OCT A-Scan From Numerical Spectral Synthesis

This is the 2D counterpart of the OCT axial-resolution simulator. Rather than evaluating a closed-form Gaussian coherence-envelope formula, this engine discretizes the broadband source's power spectrum into dozens of individual wavelength components, coherently sums each one's interference contribution at every depth, and recovers the familiar coherence-gated envelope by in-phase/quadrature demodulation — the same bottom-up approach a spectral-domain OCT processing pipeline uses. A 2D schematic of the Michelson interferometer shows the reference and sample arms with animated beams; a zoomed raw-fringe panel reveals the actual oscillating optical carrier riding beneath the envelope near the current mirror position; and a full A-scan panel plots the demodulated envelope across the whole scan range. The axial resolution readout is measured directly from this synthesized signal's own full-width-half-max, not assumed from a formula, so tuning wavelength and bandwidth shows the resolution/bandwidth trade-off emerge numerically — including where the usual textbook approximation starts to break down.