FTIR Michelson Interferometer Simulator

⚡ Performing Fourier Transform

Computing the DFT of the interferogram to reveal the spectral domain.
S(ν̃) = ∫ I(δ) e^{−i2πν̃δ} dδ

Sampling interferogram points…

Nyquist criterion: Δδ ≤ 1/(2ν̃_max)

Moving Mirror Displacement (mm) 0.00

OPD δ = 2 × displacement
At δ = 0 (ZPD) all wavenumbers interfere constructively → Center Burst.

Temperature (K) — blackbody peak 1500 K Bandwidth factor 1.0×

Insert Sample

Preset molecule

Graph B shows the source attenuated by the sample. Graph C always displays the sample Absorbance A = −log₁₀ T.

Nyquist theorem: To resolve ν̃_max = 4000 cm⁻¹ the mirror step must be ≤ 1/(2 × 4000) cm = 1.25 µm.

Michelson Interferometer — top-down schematic

Graph A — Interferogram I(δ)

Graph B — Single-Beam Spectrum

Graph C — Sample Absorbance