Laser Absorption Spectroscopy

No End-calibration and physically traceable

LAS - Laser Absorption Spectroscopy (TDLAS & QCL) for gas analyzers & sensors

The highly precise Laser Absorption Spectroscopy (LAS) measurement principle is based on the absorption of specific light wavelengths by the molecules to be detected. As light source we are using laser diodes at wavelengths from the visible to the mid-infrared range, depending on the gas. By evaluating the intensity of transmitted (I) and incident light (I₀) at the detector (Lambert-Beer’s law), the current gas concentration inside the measuring chamber can be determined. Laser Absorption Spectroscopy (LAS) is a highly selective optical measurement method for gas analysis. Depending on the application, Tunable Diode Laser Absorption Spectroscopy (TDLAS) and Quantum Cascade Laser (QCL) technologies enable precise, fast and reliable gas measurements even under demanding process conditions.

The measured spectrum is compared to the theoretical spectrum based on the HITRAN database, which contains information about the gas absorption lines.
The deviation between both spectra (we call it “Spectral Correlation”) is continuously analyzed and verified. This plausibility-checking mechanism of our LAS sensors guarantees that any kind of abnormality will be detected and the user will be warned.

Technology factsheet

We have summarized the most important information about the technology, possible applications and our technical design options in a clear factsheet.

Laser Absorption Spectroscopy

Benefits at a glance

Direct physical measurement

Selective and continuous measurement from the visible to MID-IR spectral range. Real spectroscopy (no measurement of auxiliary parameters)

No cross sensitivities

The narrow-band tunable laser source ensures highest selectivity for the measured gas. By choosing the ideal absorption lines, other gases have no influence on the measurement

Spectral correlation check

A continuous comparison of measured and theoretical spectrum is done and visualized as “Spectral Correlation”. It helps the user to see whether his measuring results are plausible or not.

No condensation, fast response time, low adsorption effects

As the pressure and temperature stabilized measuring chamber is operated in vacuum state, it is (thanks to the correspondingly lowered dew-point) protected from formation of condensate. The high (adjustable) flow, together with the vacuum, enables a fast response time and reduces adsorption and delay effects to a minimum.

Operation without consumables

No calibration gas, chemical substances or exchange of service parts required. Minimum operating costs.

TDLAS and QCL

Available with Tunable Diode Laser Absorption Spectroscopy (TDLAS) and Quantum Cascade Laser (QCL) technologies depending on the target gas and application

Laser Absorption Spectroscopy

What we offer

LAS gas analyzers

Click here for our range of customer-specific tunable diode laser spectroscopy (TDLAS) analyzers

Analyzers →

LAS gas sensors

Click here for our range of customer-specific tunable diode laser spectroscopy (TDLAS) OEM sensors

OEM sensors →

Need help?

We look forward to help you choose the perfect gas analysis products for your needs. Talk to us about different technologies and our customer-specific analyzers or OEM sensors using TDLAS and QCL laser absorption spectroscopy.