Modular Chemical Sensor Technologies for Environmental Monitoring and Biomedical Optical Diagnostics

This presentation will focus on recent advances of mid-infrared quantum cascade laser based sensors for the detection, quantification, and monitoring of trace gas species as well as their applications to environmental monitoring and medical diagnostics. The development of compact trace gas sensors, in particular those based on quantum cascade (QCL) and interband cascade (IC) lasers, permits the targeting of strong fundamental rotational-vibrational transitions in the mid-IR [1]. Trace gas detection at ppbv (parts per billion in volume) and sub-ppbv concentration levels requires sensitivity enhancement schemes such as a multipass optical cell, a cavity absorption enhancement technique, or quartz enhanced photo-acoustic absorption spectroscopy (QEPAS) [1,2]. These three spectroscopic methods can achieve minimum detectable absorption losses in the range from 10-8 to 10-11 cm-1/√Hz.