Laser spectroscopy is a technique used to measure concentration of molecules in various applications like pollution monitoring, process control or non-invasive medical monitoring. Indeed, most molecules absorb infrared light at specific wavelengths and therefore, by tuning our infrared laser at the right wavelength and shining it on a given gas, liquid or solid sample, our clients can determine the amount of molecules present in the sample with the right detection setup (using pyroelectric detectors or photoacoustics for example).
One core parameter of successful laser spectroscopy is the selected wavelength and mirSense offers its clients the unprecedented 10 to 19 microns wavelength spectrum. MirSense may manufacture a customized laser going up to 26µm emission wavelength with cryogenic cooling. The production of QCL lasers in the 10-19 microns range is unique in the world as mirSense holds an exclusive license of this technology developed at the University of Montpellier, France. In this long wave wavelength region, customers can detect various molecules like OH radicals, BTEX or hydrogen cyanide (see below some examples). Furthermore at these long wavelengths, the intrapulse linewidth broadening is relatively smaller than in the mid-infrared region and therefore, pulsed operation can be more attractive for spectroscopy.
The uniMir lasers are mounted on a thermoelectric cooler (TEC) inside a sealed High Heat Load (HHL) package integrating a collimation lens and a thermistor to readout the laser chip temperature. By controlling the chip’s operating temperature through the TEC element inside the laser’s package, customers tune the emission wavelength without mode hopping while keeping a single-mode operation.
HHL-package diagram showing the built-in thermistor that monitors the laser chip temperature and the base plate that dissipates the heat generated by the laser and the TEC.
Example of emission spectra as a function of the chip temperature for a QCL emitting at the wavelength of 17.7 µm. These DFB lasers are single mode with a side mode suppression ratio larger than 25dB. Spectra were measured using a Bruker Invenio FTIR spectrometer. The observed linewidth is limited by the spectrometer resolution (0.2 cm-1). The real linewidth is typically smaller than 200 MHz (0.006 cm-1).
Typical output characteristics of a DFB QCL emitting at 13.5µm.
Please read below some of our customer success case studies :
Infrared Detection – THz Gap: QCLs Solve Unique Problems and Save You Time, Money, and Effort
Pdf:Infrared Detection – THz Gap – QCLs Solve Unique Problems and Save You Time, Money, and Effort
Working towards clean energy
Pdf: Ignition time delay CO2_UCF_case study_mirSense
Intrapulse spectroscopy
Pdf:MirSense case study_PTB_DrZhechaoQU_IntrapulseSpectroscopy
The quest for a robust sensor for the OH radical
Pdf: 202411 Case study_UCLA OH spectroscopy_RPMC laser mirSense
When QCLs meet cold molecules
Pdf: 2026_Molecular clock case study 17um QCL_mirSense
Some publications with our lasers
You may read below a publication about OH radical spectroscopy with a 19µm QCL wavelength from mirSense.
The mirSense driver has the unique ability to pulse the qcl laser at fast MHz rates, allowing customers to scan the line of absorption of the molecules during a few hundreds of ns to detect molecules by intrapulse spectroscopy. This poster presented at the 2026 FLAIR conference presents some of the work done at the UCLA and PTB organizations.
UCLA-PTB-mirSense poster FLAIR 2026_Intrapulse Spectroscopy
The Spearrin group at UCLA presented an article at the aerospace conference AIAA SciTech about the detection of the hydroxyl radical in a rocket combustion application with a mirSense QCL at 18.8µm wavelength.
“Hydroxyl Radical Distributions in Shear Coaxial Methane-Oxygen Combustion via Rotational Laser Absorption Tomography”
Angel S. Quiroz, Provence Barnouin, Emily Fee, Ariya L. Olaee, Raymond M. Spearrin
https://doi.org/10.2514/6.2026-1895
mirSense can manufacture any wavelength in the 10-19 µm range and below are examples of gases that can be measured by spectroscopy at specific wavelengths.
General datasheet presenting the 10-19 µm offer
| Application family |
Wavelength | Measurable species | QCL product datasheet when available | |
| OH Hydroxyl radical spectroscopy | ~18.8 µm | ~531 cm-1 | OH radical | UN0530Q003HNA |
| Fundamental science | ~ 17.7 µm | ~ 565 cm-1 | UN0565C002HNA | |
| Carbon emissions | ~ 15 µm | CO2 | ||
|
Fluoro |
~ 10.5 µm | ~ 948 cm-1 | SF6 Sulfur hexafluoride | |
| VOC | ~ 13.7 µm | ~ 729 cm-1 | Toluene | UN0746C005HNA |
| VOC | ~ 14.4 µm | ~ 694 cm-1 | Toluene | |
| VOC | ~ 14.3 µm | ~ 697 cm-1 | Ethylbenzene | |
| VOC | ~ 13 µm | ~ 769 cm-1 | m-Xylene | UN0746C005HNA |
| VOC | ~ 12.6 µm | ~ 795 cm-1 | p-Xylene | UN0746C005HNA |
| VOC | ~ 13.5 µm | ~ 741 cm-1 | o-Xylene | UN0746C005HNA |
| Nitrogen | ~ 10.7 µm | ~ 930 cm-1 | NH3 Ammonia | |
| Nitrogen | ~ 17.2 µm | ~ 581 cm-1 | Nitrous oxide N2O | |
| Nitrogen | ~ 10.6 µm | ~ 941 cm-1 | N2H4 Hydrazine | |
| Nuclear | ~ 11.3 µm | ~ 885 cm-1 | CH3i Methyl Iodide | UN0885C010HNA |
| Toxic | ~ 11.8 µm | ~ 850 cm-1 | COCl2 Phosgene | |
| Toxic | ~ 14 µm | ~ 713 cm-1 | HCn Hydrogen cyanide | UN0713C005HNA |
At the Photonics West 2021 laser show, mirSense was a finalist at the Prism Award in the category smart sensing for the uniMir quantum cascade lasers that allow new spectroscopy applications in the 10 to 17 microns wavelength spectrum like Benzene detection or OH radical measurement.
Ask Adrien Dequaire
Adrien is in charge of our laser solutions
