Optofluidic Fabry-Pérot sensor for water solutions at high flow rates

Optofluidic sensor for water solutions has been fabricated using a transfer adhesive film and simple all-room-temperature procedures. Performance of a Fabry-Perot (FP) cavity subjected to the high water throughput of ∼ 2 ml per 1 min (at a 0.8 m/s flow velocity) was spectrally characterized. The 25-μm-wide cavity can be repeatedly subjected to pressures causing up to a 1.5% its width’s increase upon pressure cycling. Potential of the new optofluidic platform for applications where (i) large water volumes should be filtered as well as (ii) for measurements of turbulence onset in two-dimensional flows at high 1 m/s velocity are discussed. We show possibility to use FP cavity for the pressure sensing at sensitivity of Δλ/ΔP ≃ 0.075 nm/Pa and for the refractive index sensing at Δλ/Δn ≃ 390 nm per the refractive index unit.