Near-Infrared PCF Sensor With Ultra-High Sensitivity Detection Based on Surface Plasmon Resonance

This article proposes a surface plasmon resonance (SPR) sensor that can achieve ultra-high sensitivity detection in the near-infrared (NIR) region. Molybdenum disulfide (MoS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>) in transition metal disulfide compound materials is used as a composite film material to modulate the spectral detection range of the sensor. The sensor probe also uses a photonic crystal fiber (PCF) with a large cladding area as a substrate. From a theoretical perspective, the modulation of the MoS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film thickness was investigated to shift the resonance valley moving from the visible light band to the NIR band, effectively improving the detection sensitivity. The feasibility and effectiveness of the designed sensor in the NIR band sensing test were verified by simulation. The experimental test results show that the maximum refractive index (RI) sensitivity of the NIR sensor is as high as 25800 nm/RIU when the RI is between 1.415 and 1.420. To further investigate the temperature sensing performance of the NIR band sensor, a layer of PDMS thin film was deposited on the MoS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> film surface of the sensor for temperature testing. Its temperature test range is from 0 °C to 100 °C, with a maximum temperature sensitivity of 9.81 nm/°C. This NIR sensor is not only easy to prepare but also has ultra-high sensitivity in parameter detection, which provides a new direction for the development of SPR sensing technology in the NIR field.