Ultrasensitive optofluidic coupled Fabry–Perot capillary sensors

Abstract

Refractive index (RI) measurements are pertinent in concentration and biomolecular detection. Accordingly, an ultrasensitive optofluidic coupled Fabry–Perot (FP) capillary sensor based on the Vernier effect for RI sensing is proposed. Square capillaries integrated with the coupled FP microcavity provide multiple microfluidic channels while reducing the complexity of the fabrication process. The incoherent light source and spectrometer used during measurement facilitate the development of a low-cost sensing system. An ultrahigh RI sensitivity of 51709.0 nm/RIU and detection limit of 2.84 × 10−5 RIU are experimentally demonstrated, indicating acceptable RI sensing performance. The proposed sensor has significant potential for practical and low-cost applications such as RI, concentration, or biomolecular sensing.

Multimode sensing based on optical microcavities

“…Zhao et al proposed combining the Vernier effect with an optical microcavity to further improve sensitivity. By integrating a square capillary with a coupled FP microcavity, multiple microfluidic channels can be provided, while also reducing the complexity of the manufacturing process [ 51 ]. The Vernier effect is generated by modulation of the spectral envelope due to the mode coupling of two cavities with different free spectral ranges.…”

Optical Fiber Fabry–Pérot Microfluidic Sensor Based on Capillary Fiber and Side Illumination Method

“…Microfluidics refers to the liquids and gases that flow in the space at the micron or nanometer level. In the past few decades of fluid sensing research, the microfluidic detection technology has become one of the most important branches in the field [ 1 , 2 , 3 , 4 , 5 , 6 ]. Among them, refractive index (RI) detection is a property that can be used to infer the properties of fluids.…”