Tip-Enhanced Raman Imaging: 2D Near-Field Raster Map

Tip & Gap

Tip–sample gap d 0.6 nm

Tip apex radius a 15 nm

Laser wavelength λ 560 nm

Move the mouse over the sample to probe the near field live at any (x, y). Or run the raster scan to build a real two-dimensional Raman image, row by row.

Live Readouts

Enhancement factor

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Lateral resolution

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Raman signal (probe position)

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How it works

This is the 2D counterpart to the 3D TERS simulator: instead of a perspective view of a tip scanning a single line, it plots the plasmonic near field directly over a real two-dimensional sample plane (x, y in nanometres) and performs a genuine 2D raster scan — the actual imaging mode a real TERS instrument uses — rather than the 3D version's one-dimensional line scan.

Same gap-mode physics as the 3D model, generalized from a 1D lateral offset to a full 2D lateral distance r = √(Δx² + Δy²) between the probe point and a molecule:

g(d) = a / (a + d)
EF(d,λ) = g(d)¹² × L(λ) × 3×10&sup7;
L(λ) = 1 / (1 + ((λ−λ_res)/Γ)²),  λ_res = 500 + 2a nm,  Γ = 45 nm
r_eff = √((a+d)² + Δx² + Δy²)
signal(x,y) = 1 + EF(d,λ) × ( (a+d) / r_eff )¹²
resolution Δx ≈ √(a × d)

Setting Δy = 0 collapses this back exactly to the 3D model's formula — the physics is identical, only the imaging geometry is genuinely 2D here: five molecules are scattered across both x and y, so a 1D line scan (as in the 3D version) would only ever see whichever molecules happen to lie on that one line. The 2D raster below sees all five and reveals their true spatial layout at a resolution set by √(a·d), far below the optical diffraction limit.

Manual probe — move the mouse over the sample; the live footprint (an amber glow) follows the cursor and the readouts update instantly from the analytic formula.
Start 2D Raster Scan — sweeps a virtual tip across the entire plane, row by row, painting the true Raman intensity at every (x,y) — a real super-resolution image, not a flattened line.
Gap / radius / wavelength sliders — identical trade-offs to the 3D model: shrinking the gap spikes enhancement, a sharper tip trades peak signal for resolution, and the wavelength peaks at the tip's plasmon resonance.

Near-field / hot spot Molecule

manual probe