Dual quantum cascade lasers for noninvasive glucose detection using photoacoustic spectroscopy

The experimental setup of the dual QCLs and PA spectroscopy for noninvasive glucose detection is shown in Fig. 5. In the developed setup, two single-wavelength QCLs were employed. The first QCL was at a glucose fingerprint of 9.25 \(\upmu\)m (1080 cm\(^{-1}\)) (QD9500CM1, Thorlabs, Newton, NJ, USA), and the second was employed as a reference to the measurements lasing at 10.3 \(\upmu\)m (970 cm\(^{-1}\)) (QD10500CM1, Thorlabs, Newton, NJ, USA). The threshold currents of the 9.25 \(\upmu\)m and 10.3 \(\upmu\)m QCLs are around 180 mA and 280 mA, respectively. The light beams of the dual…