Hollow-waveguide gas sensing with room-temperature quantum cascade lasers

Hollow waveguide as an online microliter spectroscopy sensor for gas chromatography

“…Compared to previous results where gas sample and IR injections happen at the same input and exit ports for hollow waveguides [1][2][3] , our design emphasizes the ability to couple with GC line, and maintain the gas peaks before and after the IR gas sensing measurement. The ability to couple to GC columns enhances the HW IR spectroscopy sensor capability because the GC column purifies the samples by separating each sample from a mixture.…”

Proof-of-principle of surface detection with air-guided quantum cascade lasers

“…The use of QC lasers as monochromatic sources for chemical sensing is motivated by the fact that most molecules of chemical interest exhibit roto-vibrational transitions in the two mid-IR atmospheric windows [8,9]. In particular, QC lasers have been applied to gas sensing [8,10,11,12], but also more recently to detection in a liquid environment [13,14,15,16,17]. For detection applications, wavelength tunability is an important requirement, besides single-mode operation.…”

“…The principle has already been demonstrated -using mid-infrared fibers -in Ref [12,13]. One other strategy has been recently shown -using common solvents as test liquids -in Ref.…”

Microfluidic tuning of distributed feedback quantum cascade lasers

“…Alternative detection techniques include for example sensors based on hollow fibers [10]. Although it is very promising, only little work has been done to develop QCL-based techniques enabling the quantification of specific compound levels in liquids.…”