Designing Tunable Microstructure Spectroscopic Gas Sensor Using Optofluidic Hollow-Core Photonic Crystal Fiber

A tunable slow-light hollow-core photonic crystal fiber (HPCF), applicable to miniaturized microstructure spectroscopic gas sensors is proposed. In the proposed structure, we have taken the advantage of the microfluidic infiltration technique to tune the slow-light regime so as to match the reference absorption line of the target gas sample, which is required for designing miniaturized gas sensors with reconfigurable detection sensitivity. The main feature of this structure is that the enhanced electrical field is strongly localized in the hollow-core of a photonic crystal fiber for any gas samples due to tunability of slow-light modes. We discuss the potential of slow light in HPCF for realizing compact and tunable gas sensor devices with low and high loss material. In particular, we present numerical results showing how this optofluidic microstructure can be used for detecting CO, CO₂, H₂S, CH₄, SO₂, and N₂O gases.