Inside an FTIR analyser
Explore the optical path inside an FTIR gas analyser. An interactive illustration of the interferometer, heated gas cell and resulting spectrum.
FTIRexplained
Light. Molecules. Insight.
Inside an FTIR analyser.
Follow the light from source to spectrum. Explore how an infrared beam
reveals the gases in a sample, one molecular fingerprint at a time.
Interactive explainer
Follow the optical path
A closer look inside
Scanning
Swipe the diagram to follow the full optical path →
- IR beam
- Modulated IR
- Reference laser
- Gas flow
- Mirror
Explore the measurement
A longer scan gives a sharper spectrum. The displayed value is illustrative spectral resolution.
Modulate the light
A moving mirror changes the optical path, encoding infrared wavelengths into an interference signal.
Meet the molecules
The beam passes through the gas several times. Molecules absorb light at characteristic wavelengths.
Reveal the fingerprint
A Fourier transform converts the detector signal into a spectrum, revealing the sample’s absorption bands.