Fast and sensitive wavelength modulation gas spectroscopy in micro-drilled hollow-core fiber

Area of Science:

• Optics and Photonics
• Spectroscopy
• Materials Science

Background:

• Hollow-core fiber sensors typically suffer from slow gas diffusion and filling times.
• Laser-based spectroscopic gas sensing requires efficient interaction between light and the sample gas within the fiber.

Purpose of the Study:

• To demonstrate micro-drilled anti-resonant fibers as a practical tool for rapid acetylene sensing.
• To overcome the slow filling time limitations of conventional hollow-core fiber sensors.

Main Methods:

• Microchannels were precisely drilled into anti-resonant fibers using image processing.
• Wavelength modulation spectroscopy was employed to enhance detection sensitivity.
• A mixture of acetylene and methane in air was analyzed in the near-infrared spectrum.

Main Results:

• A 1 m micro-drilled fiber achieved a minimum detection limit of 380 parts per billion for acetylene.
• This sensor demonstrated a fiber filling time of 22 seconds without a pressure differential.
• Shorter fiber lengths (30 cm) with closer microchannels showed even faster filling times (4.2 seconds).

Conclusions:

• Micro-drilled anti-resonant fibers provide a viable and efficient platform for laser-based acetylene spectroscopy.
• The developed method significantly reduces gas sensing response times compared to traditional hollow-core fiber techniques.
• This technology holds promise for real-time, sensitive gas detection applications.