scholarly journals Sensing chlorinated hydrocarbons via miniaturized GaAs/AlGaAs thin-film waveguide flow cells coupled to quantum cascade lasers

2016 ◽  
Vol 8 (36) ◽  
pp. 6602-6606 ◽  
Author(s):  
Julian Haas ◽  
Robert Stach ◽  
Markus Sieger ◽  
Zana Gashi ◽  
Matthias Godejohann ◽  
...  

Mid-infrared (MIR) sensors based on attenuated total reflection (ATR) spectroscopy provide robust, rapid and sensitive platforms for the detection of low levels of organic molecules and pollutants.

2021 ◽  
pp. 000370282110643
Author(s):  
Andrea Teuber ◽  
Robert Stach ◽  
Julian Haas ◽  
Boris Mizaikoff

An innovative mid-infrared spectroscopic sensor system based on quantum cascade lasers has been developed. The system combines the versatility of substrate-integrated hollow waveguides (IHWGs) with the robustness of attenuated total reflection (ATR) crystals employed as internal reflection waveguides for evanescent field sensing. IHWGs are highly reflective metal structures that propagate infrared (IR) radiation and were used as light pipes for coupling radiation into the ATR waveguide. The combined IHWG-ATR device has been designed such that the utmost stability and robustness of the optical alignment were ensured. This novel assembly enables evanescent field absorption measurements at yet unprecedently harsh conditions, that is, high pressure and temperature. Combining these advantages, this innovative sensor assembly is perfectly suited for taking ATR spectroscopy into the field where the robustness of the assembly and optical alignment is essential.


Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5130 ◽  
Author(s):  
Ine L. Jernelv ◽  
Karina Strøm ◽  
Dag Roar Hjelme ◽  
Astrid Aksnes

The development of rapid and accurate biomedical laser spectroscopy systems in the mid-infrared has been enabled by the commercial availability of external-cavity quantum cascade lasers (EC-QCLs). EC-QCLs are a preferable alternative to benchtop instruments such as Fourier transform infrared spectrometers for sensor development as they are small and have high spectral power density. They also allow for the investigation of multiple analytes due to their broad tuneability and through the use of multivariate analysis. This article presents an in vitro investigation with two fiber-coupled measurement setups based on attenuated total reflection spectroscopy and direct transmission spectroscopy for sensing. A pulsed EC-QCL (1200–900 cm − 1 ) was used for measurements of glucose and albumin in aqueous solutions, with lactate and urea as interferents. This analyte composition was chosen as an example of a complex aqueous solution with relevance for biomedical sensors. Glucose concentrations were determined in both setup types with root-mean-square error of cross-validation (RMSECV) of less than 20 mg/dL using partial least-squares (PLS) regression. These results demonstrate accurate analyte measurements, and are promising for further development of fiber-coupled, miniaturised in vivo sensors based on mid-infrared spectroscopy.


2016 ◽  
Vol 213 (8) ◽  
pp. 2117-2123 ◽  
Author(s):  
Ángela I. López-Lorente ◽  
Pei Wang ◽  
Markus Sieger ◽  
Ernesto Vargas Catalan ◽  
Mikael Karlsson ◽  
...  

1996 ◽  
Vol 32 (6) ◽  
pp. 560 ◽  
Author(s):  
J. Faist ◽  
F. Capasso ◽  
C. Sirtori ◽  
D.L. Sivco ◽  
A.L. Hutchinson ◽  
...  

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Yifan Jiang ◽  
Karun Vijayraghavan ◽  
Seungyong Jung ◽  
Aiting Jiang ◽  
Jae Hyun Kim ◽  
...  

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