A Miniaturized UV-LED Based Optical Gas Sensor Utilizing Silica Waveguides for the Measurement of Nitrogen Dioxide and Sulphur Dioxide

Abstract

Continuing advances in the development of light-emitting diodes (LEDs) in the deep ultraviolet spectral range (DUV) enable miniaturized, mobile, and cost-effective DUV gas sensors. Efficient light coupling, guiding, and splitting plays a key role for stable sensor systems and is realized by lowloss silica based waveguides, fabricated by ultrashort pulsed laser etching and laser polishing. The tapered waveguide leads to a significantly higher efficiency with less required space compared to optical fibers or free beam setups, respectively. Toxic gases like NO2 and SO2 were successfully measured down to 1 ppm utilizing LEDs with wavelengths of 395 nm and 280 nm.

Keywords

• gas sensor
• waveguide
• UV
• LED
• absorption spectroscopy
• laser processing
• glass