A large-area single-filament infrared emitter and its application in a spectroscopic ethanol gas sensing system

Nondispersive infrared (NDIR) spectroscopy is an important technology for highly accurate and maintenance-free sensing of gases, such as ethanol and carbon dioxide. However, NDIR spectroscopy systems are currently too expensive, e.g., for consumer and automotive applications, as the infrared (IR) emitter is a critical but costly component of these systems. Here, we report on a low-cost large-area IR emitter featuring a broadband emission spectrum suitable for small NDIR gas spectroscopy systems. The infrared emitter utilizes Joule heating of a Kanthal (FeCrAl) filament that is integrated in the base substrate using an automated high-speed wire bonding process, enabling simple and rapid formation of a long meander-shaped filament. We describe the critical infrared emitter characteristics, including the effective infrared emission spectrum, thermal frequency response, and power consumption. Finally, we integrate the emitter into a handheld breath alcohol analyzer and show its operation in both laboratory and real-world settings, thereby demonstrating the potential of the emitter for future low-cost optical gas sensor applications.