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← Raman Tools

Raman Tools

Converter: Raman shift ↔ wavelength

A Raman spectrum is described in terms of shift (cm⁻¹) relative to the laser, but the detector „sees" wavelength (nm). This converter calculates one from the other for any laser. Enter a number in one field — the other will be calculated automatically.

Select excitation laser

Scattered wavelength (Stokes)
Absolute wavenumber of scattered light
Wavelength shift Δλ relative to the laser
Anti-Stokes side (corresponding wavelength)

Simple converter: nm ↔ cm⁻¹ (absolute)

Without laser — pure conversion of wavelength to absolute wavenumber and vice versa (ν̃ = 10⁷ / λ).

Photon energy and spectral units

Converter for light of a given wavelength: photon energy and equivalent units. Enter one value — the rest will be calculated automatically. Note: these are absolute values (wavelength / photon energy), not Raman shift.

Spectrally does this. Want to measure your compound with a selected laser — in the lab or directly on the line? Let's discuss your case.

How it works — formula and why it matters

Raman is measured as a shift in energy relative to the laser, not as an absolute wavelength. Thus, the same peak (e.g., 1000 cm⁻¹ for an aromatic ring) appears at the same spectral position regardless of the laser used — making it easier to compare with correlation tables.

Δν̃ [cm⁻¹] = 10⁷ · ( 1/λ₀[nm] − 1/λ[nm] )
λ_stokes [nm] = 10⁷ / ( 10⁷/λ₀ − Δν̃ )

λ₀ — laser wavelength, λ — scattered light wavelength, Δν̃ — Raman shift. The Stokes side (Δν̃ > 0) corresponds to light with a longer wavelength than the laser; the anti-Stokes side lies symmetrically at shorter wavelengths.

Practical application: check whether your peak falls within the detector range, select an edge filter, or compare measurements from two different lasers.

Have a sample you don’t want to guess about?

We conduct feasibility studies even on the most challenging samples — on your material, at your site. Leave your contact, and we will review your case and tell you directly whether Spectrally can measure it.

Write to us and learn more

Aleksandra Łukasiewicz

Aleksandra Łukasiewicz

Head of International Sales