A Compact Mid-Infrared Spectroscopy System for Healthcare Applications Based on a Wavelength-Swept, Pulsed Quantum Cascade Laser

A mid-infrared spectroscopic system using a high-speed wavelength-swept and pulsed quantum cascade laser (QCL) for healthcare applications such as blood glucose measurement is proposed. We developed an attenuated total reflection measurement system comprising the QCL with a micro-electromechanical system (MEMS)-scanning grating, hollow optical fibers, and InAsSb detector and tested its feasibility for healthcare applications. A continuous spectrum was obtained by integrating comb-shaped spectra, the timing of which was slightly shifted. As this method does not require complex calculations, absorption spectra are obtained in real-time. We found that the signal-to-noise ratio of the obtained spectrum had been improved by increasing the number of spectra that were integrated into the spectrum calculation. Accordingly, we succeeded in measuring the absorption spectrum of a 0.1% aqueous glucose solution. Furthermore, the absorption spectra of human lips were measured, and it was shown that estimation of blood glucose levels were possible using a model equation derived using a partial least squares regression analysis of the measured absorption spectra. The spectroscopic system based on the QCL with MEMS-scanning grating has the advantages of compactness and low cost over conventional Fourier transform infrared-based systems and common spectroscopic systems with a tunable QCL that has a relatively large, movable grating.

Download Full-text

High-Speed Mid-Infrared Frequency Modulation Spectroscopy Based on Quantum Cascade Laser

IEEE Photonics Technology Letters ◽

10.1109/lpt.2016.2554359 ◽

2016 ◽

Vol 28 (16) ◽

pp. 1727-1730 ◽

Cited By ~ 3

Author(s):

Chen Peng ◽

Gang Chen ◽

Jianping Tang ◽

Lijun Wang ◽

Zhongquan Wen ◽

...

Keyword(s):

Quantum Cascade Laser ◽

Frequency Modulation ◽

High Speed ◽

Mid Infrared ◽

Modulation Spectroscopy ◽

Quantum Cascade

Download Full-text

Applications of Quantum Cascade Laser Spectroscopy in the Analysis of Pharmaceutical Formulations

Applied Spectroscopy ◽

10.1177/0003702816662609 ◽

2016 ◽

Vol 70 (9) ◽

pp. 1511-1519 ◽

Cited By ~ 8

Author(s):

Nataly J. Galán-Freyle ◽

Leonardo C. Pacheco-Londoño ◽

Andrés D. Román-Ospino ◽

Samuel P. Hernandez-Rivera

Keyword(s):

Infrared Spectroscopy ◽

Laser Spectroscopy ◽

Quantum Cascade Laser ◽

Near Infrared ◽

Limit Of Detection ◽

Active Pharmaceutical Ingredient ◽

Attenuated Total Reflection ◽

Analytical Sensitivity ◽

Mid Infrared ◽

Quantum Cascade

Quantum cascade laser spectroscopy was used to quantify active pharmaceutical ingredient content in a model formulation. The analyses were conducted in non-contact mode by mid-infrared diffuse reflectance. Measurements were carried out at a distance of 15 cm, covering the spectral range 1000–1600 cm−1. Calibrations were generated by applying multivariate analysis using partial least squares models. Among the figures of merit of the proposed methodology are the high analytical sensitivity equivalent to 0.05% active pharmaceutical ingredient in the formulation, high repeatability (2.7%), high reproducibility (5.4%), and low limit of detection (1%). The relatively high power of the quantum-cascade-laser-based spectroscopic system resulted in the design of detection and quantification methodologies for pharmaceutical applications with high accuracy and precision that are comparable to those of methodologies based on near-infrared spectroscopy, attenuated total reflection mid-infrared Fourier transform infrared spectroscopy, and Raman spectroscopy.

Download Full-text

Evaluation of a Novel Noninvasive Blood Glucose Monitor Based on Mid-Infrared Quantum Cascade Laser Technology and Photothermal Detection

Journal of Diabetes Science and Technology ◽

10.1177/1932296820936634 ◽

2020 ◽

Vol 15 (1) ◽

pp. 6-10

Author(s):

Thorsten Lubinski ◽

Bartosz Plotka ◽

Sergius Janik ◽

Luca Canini ◽

Werner Mäntele

Keyword(s):

Blood Glucose ◽

Quantum Cascade Laser ◽

Machine Learning Algorithms ◽

Full Data ◽

Data Set ◽

Mid Infrared ◽

Quantum Cascade ◽

Noninvasive Measurements ◽

Diabetes Patients ◽

Improved Algorithm

Background: A prototype of a noninvasive glucometer combining skin excitation by a mid-infrared quantum cascade laser with photothermal detection was evaluated in glucose correlation tests including 100 volunteers (41 people with diabetes and 59 healthy people). Methods: Invasive reference measurements using a clinical glucometer and noninvasive measurements at a finger of the volunteer were simultaneously recorded in five-minute intervals starting from fasting glucose values for healthy subjects (low glucose values for diabetes patients) over a two-hour period. A glucose range from >50 to <350 mg/dL was covered. Machine learning algorithms were used to predict glucose values from the photothermal spectra. Data were analyzed for the average percent disagreement of the noninvasive measurements with the clinical reference measurement and visualized in consensus error grids. Results: 98.8% (full data set) and 99.1% (improved algorithm) of glucose results were within Zones A and B of the grid, indicating the highest accuracy level. Less than 1% of the data were in Zone C, and none in Zone D or E. The mean and median percent differences between the invasive as a reference and the noninvasive method were 12.1% and 6.5%, respectively, for the full data set, and 11.3% and 6.4% with the improved algorithm. Conclusions: Our results demonstrate that noninvasive blood glucose analysis combining mid-infrared spectroscopy and photothermal detection is feasible and comparable in accuracy with minimally invasive glucometers and finger pricking devices which use test strips. As a next step, a handheld version of the present device for diabetes patients is being developed.

Download Full-text

Analytical performance of μ-groove silicon attenuated total reflection waveguides

The Analyst ◽

10.1039/c9an00417c ◽

2019 ◽

Vol 144 (10) ◽

pp. 3398-3404 ◽

Cited By ~ 7

Author(s):

Julian Haas ◽

Anja Müller ◽

Lorenz Sykora ◽

Boris Mizaikoff

Keyword(s):

Fourier Transform ◽

Quantum Cascade Laser ◽

Fourier Transform Infrared ◽

Total Reflection ◽

Attenuated Total Reflection ◽

Analytical Performance ◽

Mid Infrared ◽

Quantum Cascade

The analytical performance of micromachined μ-groove silicon attenuated total reflection (ATR) elements has been evaluated in a comparison of Fourier-transform infrared (FTIR) and quantum cascade laser (QCL) spectroscopy operating at mid-infrared (MIR) wavelengths.

Download Full-text