RobustATR: Substrate-Integrated Hollow Waveguide Coupled Infrared Attenuated Total Reflectance Sensors

Abstract

Featured Application: With RobustATR, we have developed an exceedingly compact and robust infrared attenuated total reflectance (IR-ATR) accessory uniquely integrating substrate-integrated hollow waveguides (iHWG) facilitating efficient coupling to quantum cascade laser (QCL) light sources. This sensing platform is particularly suited for real-world application scenarios. Small and compact mid-infrared devices are of increasing importance, as there are several applications demanding on-site and real-time measurements in harsh real-world scenarios. The RobustATR, an innovative infrared attenuated total reflectance (IR-ATR) accessory, has been developed and tested with exemplary analytes integrating a single-wavelength Fabry–Pérot quantum cascade laser as light source for testing the feasibility of a potentially miniaturized overall sensor design. Successful direct coupling of the laser radiation via substrate-integrated hollow waveguide (iHWG) coupling elements to the sensor interface could be shown, whereby exemplary analytes of environmental and medical relevance were tested, revealing the future potential for real-world applications.