About Quantum Cascade Laser Analyzers

Instantly detect and analyse gas molecules in the near and mid-infrared range with pin-point accuracy and repeatability.


Quantum Cascade Laser (QCL) Technology

QCL technology is based on a principle called Tunable Diode Laser Absorption Spectroscopy (TDLAS), which measures the concentration of species in gaseous mixtures using tunable diode lasers and laser absorption spectrometry. Compared to other measurement techniques, such as paramagnetic detectors (“PMD”) and Chemi-luminescence, TDLAS offers multi-element detection capabilities, high accuracy with a wide dynamic range, low maintenance requirements, and a long life cycle. 

The use of lasers as spectroscopic light sources allows for high resolution spectroscopy (HRS), with QCLs offering access to the valuable mid infrared (MIR) part of the electromagnetic spectrum.

How It Works

Emerson’s Quantum Cascade Laser technology offers fast, high resolution spectroscopy to detect and identify a range of molecules in the mid-infrared wavelength range. Coupled with Tunable Diode Laser (TDL) spectroscopy, a single instrument is now able to broaden insight and monitor both the near and mid-infrared range of spectroscopic light.


When power is applied to the analyzer, the QCL heats up and as the temperature rises, laser wavelengths begin to increase. The QCL then sweeps the wavelength frequencies to detect each component of interest before cooling the device to its original temperature. This patented laser chirp process occurs in under one microsecond, enabling thousands of spectra to be recorded each second.


QCL analyzers can be configured to have up to six high-resolution laser modules and measure up to twelve unique components simultaneously.

1. Optical bench base plate – superior rigidity for
continuous, high accuracy measurement that is immune to vibration and temperature changes.
2. Smart laser modules – unique and sequenced laser chirp for fast, multi-component measurement.
3. Optical path mirrors – direct light, rigid connection to base plate to ensure alignment.
4. Flow Cell - designed to extend optical path length for greater resolution of low component (or analyte) concentrations.
5. Detector - ultrafast detection of emitted light. 


Combining QCL and TDL techonologies into a single analyzer provides unmatched measurement performance and accuracy for process gas analysis. The narrow line width allows scanning of individual peaks of identified components with minimum interference and without filtration, reference cells, or chemometric manipulations.


One of QCL’s major advantages is its laser module. Rugged and compact, the packaged laser modules can be removed and easily serviced or replaced as needed. Attached securely to the analyzer’s optical bench, each module is preconfigured to detect up to two components simultaneously with no field alignment required.



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