High precision dual-modulation differential terahertz ATR sensor for liquid measurements
Xiujun Zheng, Thomas Gevart, Guilhem Gallot
Abstract
We describe a highly sensitive and stable quantum-cascade-laser-based attenuated total reflection (ATR) terahertz sensor for the detection of very low concentration solutions, using a dual-modulation differential approach and ATR geometry. This sensor offers a very high dynamic range and a long-term stability of 40 dB, which extends the potential of terahertz radiation for the analysis of liquid and biological samples. The performance is illustrated by measurements on standard solutions of ions, sugars, and proteins, for concentrations down to 1 µM.
Topics & Concepts
Terahertz radiationOpticsAttenuated total reflectionMaterials scienceTerahertz spectroscopy and technologyCascadeDynamic rangeModulation (music)Reflection (computer programming)Quantum cascade laserLaserTotal internal reflectionOptoelectronicsPhysicsChemistryInfraredChromatographyComputer scienceAcousticsProgramming languageSpectroscopy and Laser ApplicationsTerahertz technology and applicationsPhotonic and Optical Devices